CVE-2026-45866

CVEs › CVE-2026-45866

Description

In the Linux kernel, the following vulnerability has been resolved: serial: caif: fix use-after-free in caif_serial ldisc_close() There is a use-after-free bug in caif_serial where handle_tx() may access ser->tty after the tty has been freed. The race condition occurs between ldisc_close() and packet transmission: CPU 0 (close) CPU 1 (xmit) ------------- ------------ ldisc_close() tty_kref_put(ser->tty) [tty may be freed here] <-- race window --> caif_xmit() handle_tx() tty = ser->tty // dangling ptr tty->ops->write() // UAF! schedule_work() ser_release() unregister_netdevice() The root cause is that tty_kref_put() is called in ldisc_close() while the network device is still active and can receive packets. Since ser and tty have a 1:1 binding relationship with consistent lifecycles (ser is allocated in ldisc_open and freed in ser_release via unregister_netdevice, and each ser binds exactly one tty), we can safely defer the tty reference release to ser_release() where the network device is unregistered. Fix this by moving tty_kref_put() from ldisc_close() to ser_release(), after unregister_netdevice(). This ensures the tty reference is held as long as the network device exists, preventing the UAF. Note: We save ser->tty before unregister_netdevice() because ser is embedded in netdev's private data and will be freed along with netdev (needs_free_netdev = true). How to reproduce: Add mdelay(500) at the beginning of ldisc_close() to widen the race window, then run the reproducer program [1]. Note: There is a separate deadloop issue in handle_tx() when using PORT_UNKNOWN serial ports (e.g., /dev/ttyS3 in QEMU without proper serial backend). This deadloop exists even without this patch, and is likely caused by inconsistency between uart_write_room() and uart_write() in serial core. It has been addressed in a separate patch [2]. KASAN report: ================================================================== BUG: KASAN: slab-use-after-free in handle_tx+0x5d1/0x620 Read of size 1 at addr ffff8881131e1490 by task caif_uaf_trigge/9929 Call Trace: <TASK> dump_stack_lvl+0x10e/0x1f0 print_report+0xd0/0x630 kasan_report+0xe4/0x120 handle_tx+0x5d1/0x620 dev_hard_start_xmit+0x9d/0x6c0 __dev_queue_xmit+0x6e2/0x4410 packet_xmit+0x243/0x360 packet_sendmsg+0x26cf/0x5500 __sys_sendto+0x4a3/0x520 __x64_sys_sendto+0xe0/0x1c0 do_syscall_64+0xc9/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f615df2c0d7 Allocated by task 9930: Freed by task 64: Last potentially related work creation: The buggy address belongs to the object at ffff8881131e1000 which belongs to the cache kmalloc-cg-2k of size 2048 The buggy address is located 1168 bytes inside of freed 2048-byte region [ffff8881131e1000, ffff8881131e1800) The buggy address belongs to the physical page: page_owner tracks the page as allocated page last free pid 9778 tgid 9778 stack trace: Memory state around the buggy address: ffff8881131e1380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881131e1400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881131e1480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881131e1500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881131e1580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== [1]: https://gist.github.com/mrpre/f683f244544f7b11e7fa87df9e6c2eeb [2]: https://lore.kernel.org/linux-serial/20260204074327.226165-1-jiayuan.chen@linux.dev/T/#u

Overview

State: PUBLISHED
Assigner (CNA): Linux
CVSS severity: high
CVSS score: 7.1 / 10
CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Effective score: 7.1 / 10 HIGH source: CNA overview
CWE(s): —
Reserved: 2026-05-13
Published: 2026-05-27 12:15 UTC
Last updated: 2026-05-27 12:15 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/45xxx/CVE-2026-45866.json
Linked Threat: CVE-2026-45866 — CVE-2026-45866

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-05-27 14:16:58 UTC
NVD last modified: 2026-06-25 21:06:52 UTC
NVD CVSS v3.1: 7.8 / 10 HIGH source: nvd@nist.gov
NVD CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Exploitability subscore: 1.8 / 10
Impact subscore: 5.9 / 10
EPSS score: 0.0016 (probability of exploitation in next 30 days)
EPSS percentile: 5.54% vs all CVEs — higher = more likely to be exploited, as of 2026-07-26

NVD-assigned CWE(s): CWE-416 (differs from the CNA list above)

NVD / KEV / EPSS data refreshed 2026-07-27 11:13 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-32332
Assigner: Linux
Published: May 27, 2026, 12:15:46 PM
Updated: May 27, 2026, 12:15:46 PM
EUVD base score: 0.0 / 10
EUVD-reported EPSS: 0.1600
Vendors: Linux
Products: Linux (56e0ef527b184b3de2d7f88c6190812b2b2ac6bf <5e266ba8d330d3b8e5bc198f238cd8901826cfa1)

Linux (56e0ef527b184b3de2d7f88c6190812b2b2ac6bf <4e63d6f68544ae5269ac9735ae5b69b59b5b8725)

Linux (56e0ef527b184b3de2d7f88c6190812b2b2ac6bf <308e7e4d0a846359685f40aade023aee7b27284c)

Linux (56e0ef527b184b3de2d7f88c6190812b2b2ac6bf <c8c197aaa56b25a2d54f3aa07e27e228d6c08546)

Linux (patch: 6.19.4)

Linux (patch: 6.6.128)

Linux (3.11)

Linux (56e0ef527b184b3de2d7f88c6190812b2b2ac6bf <40962f2bf8cdba63af23aec95ad3f49b689e58e2)

Linux (56e0ef527b184b3de2d7f88c6190812b2b2ac6bf <331e2b7051635780edea248dd08ae2026c126f4a)

Linux (patch: 6.1.165)

Linux (patch: 5.10.252)

Linux (patch: 0)

Linux (patch: 5.15.202)

Linux (patch: 6.18.14)

Linux (56e0ef527b184b3de2d7f88c6190812b2b2ac6bf <52731ef4438155cea782fac74e547a327ab9e7c5)

Linux (56e0ef527b184b3de2d7f88c6190812b2b2ac6bf <d3c75db4e0460641dbcd274b40867e252d801da1)

Linux (patch: 6.12.75)

Linux (patch: 7.0)
Aliases: GHSA-9834-966g-q77h

ENISA description: In the Linux kernel, the following vulnerability has been resolved: serial: caif: fix use-after-free in caif_serial ldisc_close() There is a use-after-free bug in caif_serial where handle_tx() may access ser->tty after the tty has been freed. The race condition occurs between ldisc_close() and packet transmission: CPU 0 (close) CPU 1 (xmit) ------------- ------------ ldisc_close() tty_kref_put(ser->tty) [tty may be freed here] <-- race window --> caif_xmit() handle_tx() tty = ser->tty // dangling ptr tty->ops->write() // UAF! schedule_work() ser_release() unregister_netdevice() The root cause is that tty_kref_put() is called in ldisc_close() while the network device is still active and can receive packets. Since ser and tty have a 1:1 binding relationship with consistent lifecycles (ser is allocated in ldisc_open and freed in ser_release via unregister_netdevice, and each ser binds exactly one tty), we can safely defer the tty reference release to ser_release() where the network device is unregistered. Fix this by moving tty_kref_put() from ldisc_close() to ser_release(), after unregister_netdevice(). This ensures the tty reference is held as long as the network device exists, preventing the UAF. Note: We save ser->tty before unregister_netdevice() because ser is embedded in netdev's private data and will be freed along with netdev (needs_free_netdev = true). How to reproduce: Add mdelay(500) at the beginning of ldisc_close() to widen the race window, then run the reproducer program [1]. Note: There is a separate deadloop issue in handle_tx() when using PORT_UNKNOWN serial ports (e.g., /dev/ttyS3 in QEMU without proper serial backend). This deadloop exists even without this patch, and is likely caused by inconsistency between uart_write_room() and uart_write() in serial core. It has been addressed in a separate patch [2]. KASAN report: ================================================================== BUG: KASAN: slab-use-after-free in handle_tx+0x5d1/0x620 Read of size 1 at addr ffff8881131e1490 by task caif_uaf_trigge/9929 Call Trace: <TASK> dump_stack_lvl+0x10e/0x1f0 print_report+0xd0/0x630 kasan_report+0xe4/0x120 handle_tx+0x5d1/0x620 dev_hard_start_xmit+0x9d/0x6c0 __dev_queue_xmit+0x6e2/0x4410 packet_xmit+0x243/0x360 packet_sendmsg+0x26cf/0x5500 __sys_sendto+0x4a3/0x520 __x64_sys_sendto+0xe0/0x1c0 do_syscall_64+0xc9/0xf80 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f615df2c0d7 Allocated by task 9930: Freed by task 64: Last potentially related work creation: The buggy address belongs to the object at ffff8881131e1000 which belongs to the cache kmalloc-cg-2k of size 2048 The buggy address is located 1168 bytes inside of freed 2048-byte region [ffff8881131e1000, ffff8881131e1800) The buggy address belongs to the physical page: page_owner tracks the page as allocated page last free pid 9778 tgid 9778 stack trace: Memory state around the buggy address: ffff8881131e1380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881131e1400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8881131e1480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881131e1500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881131e1580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== [1]: https://gist.github.com/mrpre/f683f244544f7b11e7fa87df9e6c2eeb [2]: https://lore.kernel.org/linux-serial/20260204074327.226165-1-jiayuan.chen@linux.dev/T/#u

EUVD references (8)

Affected products (2)

Vendor	Product	Versions	Platforms
Linux	Linux	`56e0ef527b184b3de2d7f88c6190812b2b2ac6bf` (affected), `56e0ef527b184b3de2d7f88c6190812b2b2ac6bf` (affected), `56e0ef527b184b3de2d7f88c6190812b2b2ac6bf` (affected), `56e0ef527b184b3de2d7f88c6190812b2b2ac6bf` (affected), `56e0ef527b184b3de2d7f88c6190812b2b2ac6bf` (affected), `56e0ef527b184b3de2d7f88c6190812b2b2ac6bf` (affected), `56e0ef527b184b3de2d7f88c6190812b2b2ac6bf` (affected), `56e0ef527b184b3de2d7f88c6190812b2b2ac6bf` (affected)	—
Linux	Linux	`3.11` (affected), `0` (unaffected), `5.10.252` (unaffected), `5.15.202` (unaffected), `6.1.165` (unaffected), `6.6.128` (unaffected), `6.12.75` (unaffected), `6.18.14` (unaffected), `6.19.4` (unaffected), `7.0` (unaffected)	—

Affected products — CPE 2.3 (1) NVD

NVD's normalized CPE 2.3 matchers, used by vendor tools (vulnerability scanners, asset managers) for automated detection. Compare with the CNA's free-text "Affected products" section above.

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

Vendor references (8)

References embedded in the original CVE record by the assigning CNA.

Web references (11)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

https://git.kernel.org/stable/c/308e7e4d0a846359685f40aade023aee7b27284c tenable:git.kernel.org
https://git.kernel.org/stable/c/331e2b7051635780edea248dd08ae2026c126f4a tenable:git.kernel.org
https://git.kernel.org/stable/c/40962f2bf8cdba63af23aec95ad3f49b689e58e2 tenable:git.kernel.org
https://git.kernel.org/stable/c/4e63d6f68544ae5269ac9735ae5b69b59b5b8725 tenable:git.kernel.org
https://git.kernel.org/stable/c/52731ef4438155cea782fac74e547a327ab9e7c5 tenable:git.kernel.org
https://git.kernel.org/stable/c/5e266ba8d330d3b8e5bc198f238cd8901826cfa1 tenable:git.kernel.org
https://git.kernel.org/stable/c/c8c197aaa56b25a2d54f3aa07e27e228d6c08546 tenable:git.kernel.org
https://git.kernel.org/stable/c/d3c75db4e0460641dbcd274b40867e252d801da1 tenable:git.kernel.org
https://nvd.nist.gov/vuln/detail/CVE-2026-45866 tenable:nvd.nist.gov
https://www.cve.org/CVERecord?id=CVE-2026-45866 tenable:www.cve.org
https://www.first.org/epss/ tenable:www.first.org

NVD-tagged references (8)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://git.kernel.org/stable/c/308e7e4d0a846359685f40aade023aee7b27284c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/331e2b7051635780edea248dd08ae2026c126f4a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/40962f2bf8cdba63af23aec95ad3f49b689e58e2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/4e63d6f68544ae5269ac9735ae5b69b59b5b8725 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/52731ef4438155cea782fac74e547a327ab9e7c5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/5e266ba8d330d3b8e5bc198f238cd8901826cfa1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/c8c197aaa56b25a2d54f3aa07e27e228d6c08546 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
https://git.kernel.org/stable/c/d3c75db4e0460641dbcd274b40867e252d801da1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch

Remediations (19)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

CVE-2026-41089 Netlogon RCE: Patch Domain Controllers

web:blog.gridinsoft.com

CVE - 2026 -41089 in Windows Netlogon is now reported as actively exploited. Patch domain controllers and check LSASS, Netlogon, and authentication logs.

2026-06-04 00:16 UTC
Microsoft and Adobe Patch Tuesday, May 2026 Security Update Review

web:blog.qualys.com

May 2026's Patch Tuesday arrives with Microsoft addressing a fresh set of vulnerabilities across its ecosystem, reinforcing the ongoing need for timely patching in an increasingly threat-heavy…

2026-06-04 00:16 UTC
Microsoft Patch Tuesday May 2026 - 120 Vulnerabilities Fixed, Including ...

web:cybersecuritynews.com

Microsoft's May 2026 Patch Tuesday lands with a heavy enterprise focus, fixing 120 vulnerabilities across Windows, Office, Azure, developer tools, and Microsoft 365 apps, including 29 remote code execution (RCE) flaws rated Critical.

2026-06-04 00:16 UTC
Security Update Guide - Microsoft

web:portal.msrc.microsoft.com

The Security Update Guide provides information on the latest Microsoft security updates, helping users understand and address potential vulnerabilities effectively.

2026-06-04 00:16 UTC
Portal for ArcGIS Security 2026 Update 1 Patch - Esri Support

web:support.esri.com

The C version of this patch also includes additional bug fixes not related to security, refer to the updated Issues Addressed with this Patch section for the latest details. April 20, 2026 : The 11.4 version of the Portal for ArcGIS Security 2026 Update 1 Patch is now available.

2026-06-04 00:16 UTC
April 2026 Patch Tuesday: Updates and Analysis | CrowdStrike

web:www.crowdstrike.com

Microsoft's April 2026 Patch Tuesday addresses 164 CVEs , featuring 8 Critical vulnerabilities, one exploited zero-day, and one disclosed zero-day.

2026-06-04 00:16 UTC
Windows 11 KB5083769 April 2026 update triggers death loops and BSODs

web:www.notebookcheck.net

Microsoft's Windows 11 KB5083769 April 2026 update causes critical boot failures, pixelated BSODs, and BitLocker recovery loops on Windows 11 24H2 and 25H2 PCs.

2026-06-04 00:16 UTC
Oracle Critical Patch Update Advisory - April 2026

web:www.oracle.com

This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.

2026-06-04 00:16 UTC
Windows 11 April 2026 Update tested: What's new, improved and fixed

web:www.windowslatest.com

Windows 11 April 2026 update adds Narrator Copilot support, faster Settings, File Explorer fixes, and key security improvements.

2026-06-04 00:16 UTC
Patch Tuesday June 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's June 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-06-04 00:16 UTC
Ubiquiti rushes out emergency fix for critical bug in UniFi Network ...

web:cybernews.com

Ubiquiti has released emergency updates for its UniFi Network Application - a critical vulnerability allows hackers to compromise systems without credentials.

2026-06-19 02:27 UTC
Microsoft Confirms Defender RoguePlanet 0-Day Exploit and Working to ...

web:cybersecuritynews.com

Microsoft has officially acknowledged a critical zero-day vulnerability in Microsoft Defender, publicly dubbed "RoguePlanet," and confirmed it is actively developing a security patch to address the flaw.

2026-06-19 02:27 UTC
Critical Security Vulnerabilities Alert: Latest CVE Updates and Patch ...

web:hackerdesk.com

Critical Security Vulnerabilities Alert: Latest CVE Updates and Patch Management Strategies for April 2026 This report details critical security vulnerabilities disclosed in April 2026 , including severe flaws in Fortinet, FileZen, and Microsoft products. Organizations are urged to prioritize patching based on risk assessment and leverage compensating controls to mitigate immediate threats ...

2026-06-19 02:27 UTC
Security Update Guide - Microsoft Security Response Center

web:msrc.microsoft.com

Security Update Guide - Microsoft Security Response Center

2026-06-19 02:27 UTC
May 12, 2026—Hotpatch KB5089466 (OS Builds 26200.8390 and 26100.8390 ...

web:support.microsoft.com

This Hotpatch update for Windows 11, version 25H2 and 24H2 (KB5089466) includes security improvements. To learn more about differences between security updates, optional non-security preview updates, out-of-band (OOB) updates, and continuous innovation, see Windows monthly updates explained. For information on Windows update terminology, see the different types of Windows software updates. To ...

2026-06-19 02:27 UTC
Microsoft April 2026 Patch Tuesday fixes 167 flaws, 2 zero-days

web:www.bleepingcomputer.com

Today is Microsoft's April 2026 Patch Tuesday with security updates for 167 flaws, including 2 zero-day vulnerabilities.

2026-06-19 02:27 UTC
Microsoft patches two zero-day flaws in Defender - CSO Online

web:www.csoonline.com

CISA has added the Microsoft Malware Protection Engine and Microsoft Defender Antimalware Platform vulnerabilities to its KEV catalog, suggesting exploitation in the wild.

2026-06-19 02:27 UTC
Microsoft Confirms It Is Urgently Working On Patch For ... - LinkedIn

web:www.linkedin.com

Microsoft has confirmed that it is developing a security update to address a newly disclosed zero-day vulnerability in Microsoft Defender, following the public release of exploit code that ...

2026-06-19 02:27 UTC
Microsoft working on a fix for RoguePlanet, a flaw that grants full PC ...

web:www.malwarebytes.com

Microsoft says it's working on a fix for an unpatched Defender vulnerability that can give attackers the highest level of access on Windows.

2026-06-19 02:27 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-45866.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/caif/caif_serial.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "5e266ba8d330d3b8e5bc198f238cd8901826cfa1",
              "status": "affected",
              "version": "56e0ef527b184b3de2d7f88c6190812b2b2ac6bf",
              "versionType": "git"
            },
            {
              "lessThan": "d3c75db4e0460641dbcd274b40867e252d801da1",
              "status": "affected",
              "version": "56e0ef527b184b3de2d7f88c6190812b2b2ac6bf",
              "versionType": "git"
            },
            {
              "lessThan": "4e63d6f68544ae5269ac9735ae5b69b59b5b8725",
              "status": "affected",
              "version": "56e0ef527b184b3de2d7f88c6190812b2b2ac6bf",
              "versionType": "git"
            },
            {
              "lessThan": "331e2b7051635780edea248dd08ae2026c126f4a",
              "status": "affected",
              "version": "56e0ef527b184b3de2d7f88c6190812b2b2ac6bf",
              "versionType": "git"
            },
            {
              "lessThan": "52731ef4438155cea782fac74e547a327ab9e7c5",
              "status": "affected",
              "version": "56e0ef527b184b3de2d7f88c6190812b2b2ac6bf",
              "versionType": "git"
            },
            {
              "lessThan": "c8c197aaa56b25a2d54f3aa07e27e228d6c08546",
              "status": "affected",
              "version": "56e0ef527b184b3de2d7f88c6190812b2b2ac6bf",
              "versionType": "git"
            },
            {
              "lessThan": "40962f2bf8cdba63af23aec95ad3f49b689e58e2",
              "status": "affected",
              "version": "56e0ef527b184b3de2d7f88c6190812b2b2ac6bf",
              "versionType": "git"
            },
            {
              "lessThan": "308e7e4d0a846359685f40aade023aee7b27284c",
              "status": "affected",
              "version": "56e0ef527b184b3de2d7f88c6190812b2b2ac6bf",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/caif/caif_serial.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.11"
            },
            {
              "lessThan": "3.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.252",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.202",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.165",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.128",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.75",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.14",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nserial: caif: fix use-after-free in caif_serial ldisc_close()\n\nThere is a use-after-free bug in caif_serial where handle_tx() may\naccess ser->tty after the tty has been freed.\n\nThe race condition occurs between ldisc_close() and packet transmission:\n\n    CPU 0 (close)                     CPU 1 (xmit)\n    -------------                     ------------\n    ldisc_close()\n      tty_kref_put(ser->tty)\n      [tty may be freed here]\n                     <-- race window -->\n                                      caif_xmit()\n                                        handle_tx()\n                                          tty = ser->tty  // dangling ptr\n                                          tty->ops->write() // UAF!\n      schedule_work()\n        ser_release()\n          unregister_netdevice()\n\nThe root cause is that tty_kref_put() is called in ldisc_close() while\nthe network device is still active and can receive packets.\n\nSince ser and tty have a 1:1 binding relationship with consistent\nlifecycles (ser is allocated in ldisc_open and freed in ser_release\nvia unregister_netdevice, and each ser binds exactly one tty), we can\nsafely defer the tty reference release to ser_release() where the\nnetwork device is unregistered.\n\nFix this by moving tty_kref_put() from ldisc_close() to ser_release(),\nafter unregister_netdevice(). This ensures the tty reference is held\nas long as the network device exists, preventing the UAF.\n\nNote: We save ser->tty before unregister_netdevice() because ser is\nembedded in netdev's private data and will be freed along with netdev\n(needs_free_netdev = true).\n\nHow to reproduce: Add mdelay(500) at the beginning of ldisc_close()\nto widen the race window, then run the reproducer program [1].\n\nNote: There is a separate deadloop issue in handle_tx() when using\nPORT_UNKNOWN serial ports (e.g., /dev/ttyS3 in QEMU without proper\nserial backend). This deadloop exists even without this patch,\nand is likely caused by inconsistency between uart_write_room() and\nuart_write() in serial core. It has been addressed in a separate\npatch [2].\n\nKASAN report:\n\n==================================================================\nBUG: KASAN: slab-use-after-free in handle_tx+0x5d1/0x620\nRead of size 1 at addr ffff8881131e1490 by task caif_uaf_trigge/9929\n\nCall Trace:\n <TASK>\n dump_stack_lvl+0x10e/0x1f0\n print_report+0xd0/0x630\n kasan_report+0xe4/0x120\n handle_tx+0x5d1/0x620\n dev_hard_start_xmit+0x9d/0x6c0\n __dev_queue_xmit+0x6e2/0x4410\n packet_xmit+0x243/0x360\n packet_sendmsg+0x26cf/0x5500\n __sys_sendto+0x4a3/0x520\n __x64_sys_sendto+0xe0/0x1c0\n do_syscall_64+0xc9/0xf80\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7f615df2c0d7\n\nAllocated by task 9930:\n\nFreed by task 64:\n\nLast potentially related work creation:\n\nThe buggy address belongs to the object at ffff8881131e1000\n which belongs to the cache kmalloc-cg-2k of size 2048\nThe buggy address is located 1168 bytes inside of\n freed 2048-byte region [ffff8881131e1000, ffff8881131e1800)\n\nThe buggy address belongs to the physical page:\npage_owner tracks the page as allocated\npage last free pid 9778 tgid 9778 stack trace:\n\nMemory state around the buggy address:\n ffff8881131e1380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n ffff8881131e1400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n>ffff8881131e1480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n                         ^\n ffff8881131e1500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n ffff8881131e1580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb\n==================================================================\n[1]: https://gist.github.com/mrpre/f683f244544f7b11e7fa87df9e6c2eeb\n[2]: https://lore.kernel.org/linux-serial/20260204074327.226165-1-jiayuan.chen@linux.dev/T/#u"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-27T12:15:46.135Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/5e266ba8d330d3b8e5bc198f238cd8901826cfa1"
        },
        {
          "url": "https://git.kernel.org/stable/c/d3c75db4e0460641dbcd274b40867e252d801da1"
        },
        {
          "url": "https://git.kernel.org/stable/c/4e63d6f68544ae5269ac9735ae5b69b59b5b8725"
        },
        {
          "url": "https://git.kernel.org/stable/c/331e2b7051635780edea248dd08ae2026c126f4a"
        },
        {
          "url": "https://git.kernel.org/stable/c/52731ef4438155cea782fac74e547a327ab9e7c5"
        },
        {
          "url": "https://git.kernel.org/stable/c/c8c197aaa56b25a2d54f3aa07e27e228d6c08546"
        },
        {
          "url": "https://git.kernel.org/stable/c/40962f2bf8cdba63af23aec95ad3f49b689e58e2"
        },
        {
          "url": "https://git.kernel.org/stable/c/308e7e4d0a846359685f40aade023aee7b27284c"
        }
      ],
      "title": "serial: caif: fix use-after-free in caif_serial ldisc_close()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-45866",
    "datePublished": "2026-05-27T12:15:46.135Z",
    "dateReserved": "2026-05-13T15:03:33.080Z",
    "dateUpdated": "2026-05-27T12:15:46.135Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}