Bug 2532400 (CVE-2026-80956)

Summary:	CVE-2026-80956 kernel: dm-pcache: only hand out initialized cache segments
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
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Doc Text:	A flaw was found in the Linux kernel's `dm-pcache` component. A crafted image can cause the `get_cache_segment()` function to return an uninitialized cache segment. This uninitialized segment, containing a null data pointer, is then used by `cache_kset_close()` without a proper null check. This can lead to a system crash, resulting in a Denial of Service (DoS).	Story Points:	---
Clone Of:		Environment:
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Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-11 22:47:28 UTC

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

dm-pcache: only hand out initialized cache segments

get_cache_segment() scans the segment map up to cache->n_segs, the
physical device segment count, but cache_segs_init() only initializes
the first cache_info->n_segs segments. A crafted image with
cache_info->n_segs smaller than the device count leaves the remaining
pcache_cache_segment structs zeroed (segment.data == NULL), and the
allocator can hand one to cache_kset_close(), which writes through the
returned segment's data pointer with no NULL check.

Bound the allocator's search to cache_info->n_segs so only initialized
segments are ever returned. A conforming cache sets n_segs equal to the
device segment count, so this rejects nothing legitimate.

Comment 1 Keith Grant 2026-09-14 16:26:28 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80956.mbox