Bug 2540243 (CVE-2026-93236)

Summary:	CVE-2026-93236 kernel: media: meson: vdec: fix NULL pointer deref in vdec_try_fmt_common
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 Meson video decoder driver. When processing video format negotiation requests with an unsupported format on the output queue, the driver improperly falls back to a format that may not be supported by the platform format table. This issue leads to a NULL pointer dereference, allowing a local user to cause a kernel crash and resulting in a Denial of Service (DoS).	Story Points:	---
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Last Closed:		Type:	---
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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 2026-09-24 15:52:45 UTC

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

media: meson: vdec: fix NULL pointer deref in vdec_try_fmt_common

When VIDIOC_TRY_FMT is called with an unsupported pixel format on the
OUTPUT queue, vdec_try_fmt_common() falls back to V4L2_PIX_FMT_MPEG2.
However, if a distro has locally patched MPEG2 support out (as it has
been broken for some time) the platform format table does not contain
MPEG2 so find_format() returns NULL and the subsequent dereference of
fmt_out->max_width triggers a NULL pointer dereference.

Fix this by falling back to the first format in the platform's format
array instead of hardcoding V4L2_PIX_FMT_MPEG2. This is always valid
since every platform defines at least one format.

Comment 1 Mauro Matteo Cascella 2026-09-25 13:54:36 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-93236.mbox