Bug 2532037 (CVE-2026-80957)

Summary:	CVE-2026-80957 kernel: dm-pcache: detect a cycle in the last-kset chain during replay
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
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Doc Text:	A flaw was found in the `dm-pcache` component of the Linux kernel. A local attacker could exploit a vulnerability in the `cache_replay()` function, which does not properly handle a forged `last-kset` chain. By crafting a malicious chain that points back to an already visited segment, an attacker can cause an infinite loop during replay, leading to a Denial of Service (DoS) condition.	Story Points:	---
Clone Of:		Environment:
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Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-11 20:08:54 UTC

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

dm-pcache: detect a cycle in the last-kset chain during replay

cache_replay() follows the on-media last-kset chain by next_cache_seg_id
with no cond_resched(). A forged chain that points back into a segment it
has already visited makes the replay loop follow it forever.

Cap the last-kset hops at cache->n_segs; a valid chain visits each segment
at most once.

Comment 1 Mauro Matteo Cascella 2026-09-14 14:25:07 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80957.mbox