CVE-2026-45251

Local privilege escalation via stale wait-queue entries

Published May 21, 2026 · Updated May 21, 2026

Use-after-free in the FreeBSD kernel allows local users to obtain superuser privileges through concurrent file-descriptor operations. Some file-descriptor destructors free an underlying object without first unlinking threads blocked on its per-object wait queue. An unprivileged local user must race close against poll(2) or select(2); waking the blocked thread then dereferences freed memory in kernel context.

CVSS severity7.8
High
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the FreeBSD kernel allows local users to obtain superuser privileges through concurrent file-descriptor operations. Some file-descriptor destructors free an underlying object without first unlinking threads blocked on its per-object wait queue. An unprivileged local user must race close against poll(2) or select(2); waking the blocked thread then dereferences freed memory in kernel context.

The record

CVE
CVE-2026-45251
Published
May 21, 2026
Updated
May 21, 2026
Vendor
The FreeBSD Project
Product
FreeBSD
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 2026CVE publishedPublication date reported by the CVE source.
  2. May 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=14.3-RELEASE <p14
  2. Affected versionversion=14.4-RELEASE <p5
  3. Affected versionversion=15.0-RELEASE <p9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The FreeBSD Project · FreeBSDversion=14.3-RELEASE <p14; version=14.4-RELEASE <p5; version=15.0-RELEASE <p9

Published CVSS scores

7.8CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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