Bug 2541345 (CVE-2026-98117)

Summary:	CVE-2026-98117 kernel: cachefiles: Fix potential UAF/KASAN warning
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 cachefiles subsystem. When processing cache coherency trace events, the system reads fixed-size data from a buffer that may be empty or shorter than expected. A local user could exploit this flaw to trigger an out-of-bounds memory read, resulting in a system crash and denial of service (DoS) or potential information disclosure.	Story Points:	---
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Last Closed:		Type:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-25 11:29:53 UTC

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

cachefiles: Fix potential UAF/KASAN warning

Currently, trace_cachefiles_coherency() is being passed a pointer to a
__be64 lain over the coherency data in struct cachefiles_xattr so that it
can display the first 8 bytes.  However, the data is of variable length and
could even be 0 bytes.  This could lead to a UAF or KASAN warning.

Fix this by making sure the buffer has room for at least 8 bytes and that
those 8 bytes are pre-cleared.

Further, those bytes are not 8-byte aligned, so fix the tracepoint to
extract the data as four 2-byte words (they are 2-byte aligned) and
reassemble the __be64.  The compiler will convert this into a single 8-byte
load where the CPU supports it.

Comment 1 Keith Grant 2026-09-28 12:49:20 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98117.mbox