Bug 2535273 (CVE-2026-89954)

Summary:	CVE-2026-89954 kernel: mtd: afs: validate v2 image info bounds
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:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's AFS (Andrew File System) v2 parser. This vulnerability occurs because the parser does not properly validate the image information offset and region count obtained from flash contents. An attacker with local access to manipulate flash contents could exploit this lack of validation, potentially leading to an underflow in erase block calculations or out-of-bounds memory access. This could result in a denial of service or other memory corruption issues.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-16 11:50:32 UTC

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

mtd: afs: validate v2 image info bounds

The AFS v2 parser uses footer[8] to locate the image information block
inside the current erase block, then uses the image information
region_count to walk entries from a fixed local array. The footer offset
and region count come from flash contents and are not checked against the
erase block or the local image-info array before use.

Reject v2 entries whose image information offset would underflow the
erase block calculation, and reject region counts that cannot fit in the
local image-info array before walking region entries.

Comment 1 Keith Grant 2026-09-16 18:03:24 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89954.mbox