CVE-2023-53728 Affecting kernel-headers package, versions *


Severity

Recommended
low

Based on Red Hat Enterprise Linux security rating.

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  • Snyk IDSNYK-RHEL8-KERNELHEADERS-13694209
  • published24 Oct 2025
  • disclosed22 Oct 2025

Introduced: 22 Oct 2025

NewCVE-2023-53728  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:8 kernel-headers.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-headers package and not the kernel-headers package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

posix-timers: Ensure timer ID search-loop limit is valid

posix_timer_add() tries to allocate a posix timer ID by starting from the cached ID which was stored by the last successful allocation.

This is done in a loop searching the ID space for a free slot one by one. The loop has to terminate when the search wrapped around to the starting point.

But that's racy vs. establishing the starting point. That is read out lockless, which leads to the following problem:

CPU0 CPU1 posix_timer_add() start = sig->posix_timer_id; lock(hash_lock); ... posix_timer_add() if (++sig->posix_timer_id < 0) start = sig->posix_timer_id; sig->posix_timer_id = 0;

So CPU1 can observe a negative start value, i.e. -1, and the loop break never happens because the condition can never be true:

if (sig->posix_timer_id == start) break;

While this is unlikely to ever turn into an endless loop as the ID space is huge (INT_MAX), the racy read of the start value caught the attention of KCSAN and Dmitry unearthed that incorrectness.

Rewrite it so that all id operations are under the hash lock.

CVSS Base Scores

version 3.1