CVE-2025-21893
HIGH EPSS 6.6%
Published Mar 31, 20251y ago · Modified Jun 17, 20262w ago
7.8 CVSS 3.1
Published Mar 31, 2025 1y ago
Last Modified Jun 17, 2026 2w ago
Description
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 Details
Base Score
Exploitability
Impact
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High
Threat Intelligence
EPSS Exploit Probability
6.6% percentile
Exploit & Patch Status
No Known Exploit
Patch Available
Weaknesses 1
CWE-416 Use After Free Memory Safety
Affected Products 6
References 3
- git.kernel.org https://git.kernel.org/stable/c/6afe2ea2daec156bd94ad2c5a6f4f4c48240dcd3
- git.kernel.org https://git.kernel.org/stable/c/75845c6c1a64483e9985302793dbf0dfa5f71e32
- git.kernel.org https://git.kernel.org/stable/c/f6a3cf833188e897c97028cd7b926e3f2cb1a8c0
Remediation
- git.kernel.org https://git.kernel.org/stable/c/6afe2ea2daec156bd94ad2c5a6f4f4c48240dcd3
- git.kernel.org https://git.kernel.org/stable/c/75845c6c1a64483e9985302793dbf0dfa5f71e32
- git.kernel.org https://git.kernel.org/stable/c/f6a3cf833188e897c97028cd7b926e3f2cb1a8c0