CVE-2025-21893 Affecting kernel-syms package, versions <6.4.0-150700.53.3.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.02% (3rd percentile)

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  • Snyk IDSNYK-SLES157-KERNELSYMS-10354104
  • published14 Jun 2025
  • disclosed13 Jun 2025

Introduced: 13 Jun 2025

NewCVE-2025-21893  (opens in a new tab)

How to fix?

Upgrade SLES:15.7 kernel-syms to version 6.4.0-150700.53.3.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-syms package and not the kernel-syms package as distributed by SLES. See How to fix? for SLES:15.7 relevant fixed versions and status.

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

keys: Fix UAF in key_put()

Once a key's reference count has been reduced to 0, the garbage collector thread may destroy it at any time and so key_put() is not allowed to touch the key after that point. The most key_put() is normally allowed to do is to touch key_gc_work as that's a static global variable.

However, in an effort to speed up the reclamation of quota, this is now done in key_put() once the key's usage is reduced to 0 - but now the code is looking at the key after the deadline, which is forbidden.

Fix this by using a flag to indicate that a key can be gc'd now rather than looking at the key's refcount in the garbage collector.

CVSS Base Scores

version 3.1