CVE-2026-98115
📛 CVE Title
ksmbd: safely drain sessions during logoff
Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: safely drain sessions during logoff SMB3 multichannel allows requests for one session to run on multiple connections. Wait for all channels bound to a session before freeing shared session objects. A deferred byte-range lock remains counted as a running request and only wakes when its file closes. Wake blocked locks during the drain without unpublishing or modifying their file objects. Synchronous CANCEL requests must invoke their cancellation callback to wake pending operations, while CHANGE_NOTIFY completion remains specific to the asynchronous path. Serialize session teardown with channel registration and previous-session cleanup, and use atomic work-state transitions so LOGOFF, CANCEL, and connection teardown invoke cancellation callbacks only once.
Overview
- State
- PUBLISHED
- Assigner (CNA)
- Linux
- CVSS severity
- HIGH
- CVSS score
- 8.8 / 10
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H- Effective score
- 8.8 / 10 HIGH source: CNA overview
- CWE(s)
- —
- Reserved
- 2026-09-25
- Published
- 2026-09-25 10:36 UTC
- Last updated
- 2026-09-25 14:42 UTC
- Source
- https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/98xxx/CVE-2026-98115.json
- Linked Threat
- CVE-2026-98115 — ksmbd: safely drain sessions during logoff
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
- 2026-09-25 11:17:42 UTC
- NVD last modified
- 2026-09-25 15:18:06 UTC
- NVD CVSS v3.1
- 8.8 / 10 HIGH source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H- Exploitability subscore
- 2.8 / 10
- Impact subscore
- 5.9 / 10
NVD / KEV / EPSS data refreshed 2026-09-26 04:22 UTC. Re-run the 🛰 Backfill from NVD button above to refresh.
Affected products (2)
| Vendor | Product | Versions | Platforms |
|---|---|---|---|
| Linux | Linux |
76e98a158b207771a6c9a0de0a60522a446a3447 (affected),
76e98a158b207771a6c9a0de0a60522a446a3447 (affected),
118fd997612d1efc94a86c307c6c6d659ebe29fc (affected),
c1e55020534c4aafbc38d8f5c4583ff30755ac18 (affected),
6.6.48 (affected),
6.10.7 (affected)
|
— |
| Linux | Linux |
6.11 (affected),
0 (unaffected),
7.2.7 (unaffected),
7.3-rc2 (unaffected)
|
— |
Vendor references (2)
References embedded in the original CVE record by the assigning CNA.
Web references (0)
DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.
No web references attached yet.
NVD-tagged references (2)
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/a7e6df0bb92642bee4431b2b85c69ada1e463b21 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/d12168084c8c1b6d883c8eca5853929ac5136a9e 416baaa9-dc9f-4396-8d5f-8c081fb06d67
AI Forensic Analysis
Only Available for Registered Users. Sign in to view.
Raw JSON
The full cvelistV5 record. Download as CVE-2026-98115.json.
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/smb/server/connection.c",
"fs/smb/server/mgmt/user_session.c",
"fs/smb/server/mgmt/user_session.h",
"fs/smb/server/smb2pdu.c",
"fs/smb/server/vfs_cache.c",
"fs/smb/server/vfs_cache.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "a7e6df0bb92642bee4431b2b85c69ada1e463b21",
"status": "affected",
"version": "76e98a158b207771a6c9a0de0a60522a446a3447",
"versionType": "git"
},
{
"lessThan": "d12168084c8c1b6d883c8eca5853929ac5136a9e",
"status": "affected",
"version": "76e98a158b207771a6c9a0de0a60522a446a3447",
"versionType": "git"
},
{
"status": "affected",
"version": "118fd997612d1efc94a86c307c6c6d659ebe29fc",
"versionType": "git"
},
{
"status": "affected",
"version": "c1e55020534c4aafbc38d8f5c4583ff30755ac18",
"versionType": "git"
},
{
"lessThan": "6.7",
"status": "affected",
"version": "6.6.48",
"versionType": "semver"
},
{
"lessThan": "6.11",
"status": "affected",
"version": "6.10.7",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/smb/server/connection.c",
"fs/smb/server/mgmt/user_session.c",
"fs/smb/server/mgmt/user_session.h",
"fs/smb/server/smb2pdu.c",
"fs/smb/server/vfs_cache.c",
"fs/smb/server/vfs_cache.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.11"
},
{
"lessThan": "6.11",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.7",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3-rc2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.7",
"versionStartIncluding": "6.11",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3-rc2",
"versionStartIncluding": "6.11",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.6.48",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "6.10.7",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nksmbd: safely drain sessions during logoff\n\nSMB3 multichannel allows requests for one session to run on multiple\nconnections. Wait for all channels bound to a session before freeing\nshared session objects.\n\nA deferred byte-range lock remains counted as a running request and only\nwakes when its file closes. Wake blocked locks during the drain without\nunpublishing or modifying their file objects. Synchronous CANCEL requests\nmust invoke their cancellation callback to wake pending operations, while\nCHANGE_NOTIFY completion remains specific to the asynchronous path.\n\nSerialize session teardown with channel registration and previous-session\ncleanup, and use atomic work-state transitions so LOGOFF, CANCEL, and\nconnection teardown invoke cancellation callbacks only once."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - The racing teardowns start from SMB2 messages that ksmbd receives over TCP/445. They are an SMB2 LOGOFF handled by smb2_session_logoff(), and a SESSION_SETUP carrying PreviousSessionId handled by destroy_previous_session(). Requests in flight on other bound channels are also affected. All of these are sent by the remote client.\nAC:L - The attacker controls both sides of the race by opening several TCP connections to the same session. Before the fix, smb2_session_logoff() only waited for its own connection (ksmbd_conn_wait_idle). It also had no tearing_down guard against a concurrent destroy_previous_session() or a second LOGOFF, so the attacker can retry the race at will.\nPR:L - Both LOGOFF and a PreviousSessionId reconnect need a valid authenticated session. destroy_previous_session() also checks that the user name and passkey match the previous session's user. So the attacker must be an ordinary authenticated SMB user, not an unauthenticated one.\nUI:N - The attacker's own SMB requests on their own connections drive the whole sequence. No admin or victim action is needed.\nS:U - The corruption stays within the kernel's own security authority: ksmbd session, file table and tree-connect objects. No hypervisor or IOMMU boundary is crossed.\nC:H - The session's file table can be torn down while it is still in use. ksmbd_close_session_fds() and ksmbd_destroy_file_table() can run at the same time, and requests on other channels can still hold objects from the table being freed. That makes a use-after-free or double free of kernel heap objects, which a heap spray can turn into a memory read.\nI:H - A use-after-free or double free of ksmbd_file and session objects reached from the network lets the attacker reallocate the freed memory with their own data. That can corrupt kernel memory and potentially hijack control flow.\nA:H - Freeing session objects during concurrent teardown can oops or panic the kernel. Deferred byte-range locks that never wake can also hang the drain. The attacker can repeat either on demand."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-25T14:42:07.560Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/a7e6df0bb92642bee4431b2b85c69ada1e463b21"
},
{
"url": "https://git.kernel.org/stable/c/d12168084c8c1b6d883c8eca5853929ac5136a9e"
}
],
"title": "ksmbd: safely drain sessions during logoff",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-98115",
"datePublished": "2026-09-25T10:36:01.119Z",
"dateReserved": "2026-09-25T10:25:14.317Z",
"dateUpdated": "2026-09-25T14:42:07.560Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}