Medium [CVE-2026-89655] Linux kernel Ceph: Use-After-Free vulnerability in capability message handling
This medium-severity Red Hat Linux advisory covers CVE-2026-89655.
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Summary
A flaw was found in the Linux kernel's Ceph file system component. A race condition exists in the `__kick_flushing_caps()` function during the handling of capability messages.
This allows a separate process to free a data structure (`cf entry`) while `__kick_flushing_caps()` is still iterating over it. This use-after-free (UAF) vulnerability can lead to system instability, a denial of service (DoS), or potentially privilege escalation for a local attacker.
Red Hat severity: Moderate — CVSS 5.3 (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H). Weakness: CWE-366.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
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