CVE-2025-21893

7.8 HIGH 0.2% exploit odds Fix listed Memory safety OS & kernel

What it is

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.

At a glance

Exploitability: Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.
Exploit odds: 0.2% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2025-03-31 20:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 08:44 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.2% in the next 30 days (EPSS).
Severity: 7.8 HIGH (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2025-03-31 20:15 UTC
Last modified: 2026-06-17 08:44 UTC
Exploit probability: 0.2% · EPSS, next 30 days
Weakness: CWE-416 · Use after free
Record status: Analyzed

Affected

Linux Kernel < 6.12.21
Linux Kernel < 6.13.9
Linux Kernel 6.14

Attack profile CVSS 3.1 · 7.8

Attack vector: Local
Complexity: Low
Privileges needed: Low
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Raw vector

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

Is it in your code?

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Read https://cve-list.com/agent/cve/CVE-2025-21893.md and follow it. Check whether this project is affected by CVE-2025-21893. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record