CVE-2026-45251
📛 CVE Title
Kernel use-after-free via file descriptor syscalls
Description
A file descriptor can be closed while a thread is blocked in a poll(2) or select(2) call waiting for that descriptor. Because the blocked thread does not hold a reference to the underlying object, this closure may result in the object being freed while the thread remains blocked. In this situation, the kernel must remove the blocked thread from the per-object wait queue prior to freeing the object. In the case of some file descriptor types, the kernel failed to unlink blocked threads from the object before freeing it. When the blocked thread is subsequently woken, it accesses memory that has already been freed resulting in a use-after-free vulnerability. The use-after-free vulnerability may be triggered by an unprivileged local user and can be exploited to obtain superuser privileges.
Overview
- State
- PUBLISHED
- Assigner (CNA)
- freebsd
- CVSS severity
- high
- CVSS score
- 7.8 / 10
- CVSS vector
AV:L/AC:L/Au:S/C:C/I:C/A:C- Effective score
- 7.8 / 10 HIGH source: CNA overview
- CWE(s)
-
CWE-416 - Reserved
- 2026-05-11
- Published
- 2026-05-21 09:04 UTC
- Last updated
- 2026-05-21 09:04 UTC
- Source
- https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/45xxx/CVE-2026-45251.json
- Linked Threat
- CVE-2026-45251 — CVE-2026-45251
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
- 2026-05-21 10:16:26 UTC
- NVD last modified
- 2026-05-21 19:01:22 UTC
- NVD CVSS v3.1
- 7.8 / 10 HIGH source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
- 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
- 0.0001 (probability of exploitation in next 30 days)
- EPSS percentile
- 0.34% vs all CVEs — higher = more likely to be exploited, as of 2026-05-24
NVD / KEV / EPSS data refreshed 2026-05-25 00:29 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-2026-31256 - Assigner
- freebsd
- Published
- May 21, 2026, 9:04:52 AM
- Updated
- May 22, 2026, 3:55:35 AM
- EUVD base score (CVSS 3.1)
-
7.8 / 10
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - EUVD-reported EPSS
- 0.0100
- Vendors
- FreeBSD
- Products
-
FreeBSD (14.3-RELEASE <p14)FreeBSD (15.0-RELEASE <p9)FreeBSD (14.4-RELEASE <p5)
- Aliases
-
GHSA-wp9w-fp98-2cxm
ENISA description: A file descriptor can be closed while a thread is blocked in a poll(2) or select(2) call waiting for that descriptor. Because the blocked thread does not hold a reference to the underlying object, this closure may result in the object being freed while the thread remains blocked. In this situation, the kernel must remove the blocked thread from the per-object wait queue prior to freeing the object. In the case of some file descriptor types, the kernel failed to unlink blocked threads from the object before freeing it. When the blocked thread is subsequently woken, it accesses memory that has already been freed resulting in a use-after-free vulnerability. The use-after-free vulnerability may be triggered by an unprivileged local user and can be exploited to obtain superuser privileges.
EUVD references (1)
Affected products (1)
| Vendor | Product | Versions | Platforms |
|---|---|---|---|
| FreeBSD | FreeBSD |
15.0-RELEASE (affected),
14.4-RELEASE (affected),
14.3-RELEASE (affected)
|
— |
Affected products — CPE 2.3 (29) 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:freebsd:freebsd:14.3:-:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.3:p1:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.3:p10:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.3:p11:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.3:p12:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.3:p13:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.3:p2:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.3:p3:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.3:p4:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.3:p5:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.3:p6:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.3:p7:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.3:p8:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.3:p9:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.4:-:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.4:p1:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.4:p2:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.4:p3:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.4:p4:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:14.4:rc1:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:15.0:-:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:15.0:p1:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:15.0:p2:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:15.0:p3:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:15.0:p4:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:15.0:p5:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:15.0:p6:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:15.0:p7:*:*:*:*:*:*cpe:2.3:o:freebsd:freebsd:15.0:p8:*:*:*:*:*:*
Vendor references (1)
References embedded in the original CVE record by the assigning CNA.
Web references (5)
DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.
- https://nvd.nist.gov/vuln/detail/CVE-2026-45251 tenable:nvd.nist.gov
- https://security.freebsd.org/advisories/FreeBSD-SA-26:19.file.asc tenable:security.freebsd.org
- https://www.first.org/epss/ tenable:www.first.org
- https://attackerkb.com/topics/CVE-2026-45251 rapid7:attackerkb.com
- https://www.cve.org/CVERecord?id=CVE-2026-45251 rapid7:www.cve.org
NVD-tagged references (1)
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://security.freebsd.org/advisories/FreeBSD-SA-26:19.file.asc secteam@freebsd.org Vendor Advisory
Remediations (17)
Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.
-
web:blogs.oracle.com
For more information about the Critical Patch Update program, see the security vulnerability remediation practices page located on the Oracle Trust Center.
2026-05-23 22:19 UTC -
web:blogs.oracle.com
As a follow-up to our recent post, Accelerating Vulnerability Detection and Response, Oracle is announcing the start date and cadence for monthly Critical Security Patch Updates (CSPUs). Beginning May 28, 2026 , Oracle will deliver a Critical Security Patch Update (CSPU) each month.
2026-05-23 22:19 UTC -
web:cyberpress.org
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added two actively exploited Microsoft Defender vulnerabilities to its Known Exploited Vulnerabilities (KEV) catalog, issuing an urgent remediation directive for federal agencies with a due date of June 3, 2026 .
2026-05-23 22:19 UTC -
web:krebsonsecurity.com
Microsoft expects that exploitation is more likely. May's Patch Tuesday is a welcome respite from April, which saw Microsoft fix a near-record 167 security flaws.
2026-05-23 22:19 UTC -
web:msrc.microsoft.com
Security Update Guide - Microsoft Security Response Center
2026-05-23 22:19 UTC -
web:support.servicenow.com
Overview The advisories below document publicly disclosed Common Vulnerabilities and Exposures ( CVEs ) in the Now Platform by ServiceNow. Because ServiceNow uses various methods to communicate vulnerability information, patches, and other fixes, customers should review family, security patch , and hotfix release notes, which are available at https://docs.servicenow.com, for a complete list of ...
2026-05-23 22:19 UTC -
web:www.bleepingcomputer.com
Today is Microsoft's April 2026 Patch Tuesday with security updates for 167 flaws, including 2 zero-day vulnerabilities.
2026-05-23 22:19 UTC -
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.
2026-05-23 22:19 UTC -
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.
2026-05-23 22:19 UTC -
web:www.securityweek.com
Oracle on Tuesday announced the release of 481 new security patches as part of its April 2026 Critical Patch Update (CPU). Across the 28 product families that received security updates, more than 300 patches address vulnerabilities that are remotely exploitable without authentication.
2026-05-23 22:19 UTC -
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.
2026-06-03 22:32 UTC -
web:krebsonsecurity.com
For a clickable, per- patch breakdown, check out the SANS Internet Storm Center Patch Tuesday roundup. Running into problems applying any of these updates?
2026-06-03 22:32 UTC -
web:msrc.microsoft.com
The Microsoft Security Response Center (MSRC) investigates all reports of security vulnerabilities affecting Microsoft products and services, and provides the information here as part of the ongoing effort to help you manage security risks and help keep your systems protected.
2026-06-03 22:32 UTC -
web:www.malwarebytes.com
The KEV catalog tracks vulnerabilities known to be exploited in the wild and sets patch deadlines for Federal Civilian Executive Branch (FCEB) agencies. Five of the added vulnerabilities are quite old by vulnerability standards. Patches were released in 2008, 2009, and 2010. But the Microsoft Defender vulnerabilities are from this year. Those ...
2026-06-03 22:32 UTC -
web:www.securityweek.com
Microsoft has announced mitigations for CVE - 2026 -45585, a BitLocker bypass triggered via FsTx in Windows Recovery.
2026-06-03 22:32 UTC -
web:www.virustotal.com
VirusTotal is a platform for scanning files and URLs for viruses, malware, and other threats using multiple antivirus engines.
2026-06-03 22:32 UTC -
web:zecurit.com
Get the complete breakdown of Microsoft's June 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .
2026-06-03 22:32 UTC
AI Forensic Analysis
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Raw JSON
The full cvelistV5 record. Download as CVE-2026-45251.json.
{
"containers": {
"cna": {
"affected": [
{
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"modules": [
"file"
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"product": "FreeBSD",
"vendor": "FreeBSD",
"versions": [
{
"lessThan": "p9",
"status": "affected",
"version": "15.0-RELEASE",
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},
{
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"status": "affected",
"version": "14.4-RELEASE",
"versionType": "release"
},
{
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"credits": [
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"lang": "en",
"type": "finder",
"value": "75Acol, Lexpl0it, fcgboy, and robinzeng2015"
},
{
"lang": "en",
"type": "finder",
"value": "Ryan at Calif.io"
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"datePublic": "2026-05-20T23:00:00.000Z",
"descriptions": [
{
"lang": "en",
"value": "A file descriptor can be closed while a thread is blocked in a poll(2) or select(2) call waiting for that descriptor. Because the blocked thread does not hold a reference to the underlying object, this closure may result in the object being freed while the thread remains blocked. In this situation, the kernel must remove the blocked thread from the per-object wait queue prior to freeing the object.\n\nIn the case of some file descriptor types, the kernel failed to unlink blocked threads from the object before freeing it. When the blocked thread is subsequently woken, it accesses memory that has already been freed resulting in a use-after-free vulnerability.\n\nThe use-after-free vulnerability may be triggered by an unprivileged local user and can be exploited to obtain superuser privileges."
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-416",
"description": "CWE-416: Use After Free",
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}
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}
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"references": [
{
"tags": [
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],
"url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:19.file.asc"
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