Kernel use-after-free via file descriptor syscalls_CVE-2026-45251

7.8 / 10

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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.

Basic Information

ID CVE-2026-45251

Source freebsd

Published May 21, 2026 at 09:04

Modified May 21, 2026 at 14:15

Affected Product

Vendor FreeBSD

Product FreeBSD

Version 15.0-RELEASE

Affected Versions FreeBSD FreeBSD 15.0-RELEASE
FreeBSD FreeBSD 14.4-RELEASE
FreeBSD FreeBSD 14.3-RELEASE

CWE Classification

CWE-416

References

security.freebsd.org /advisories/FreeBSD-SA-26:19.file.asc

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    "published": "2026-05-21T09:04:52.569Z",
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