Bug 2516826 (CVE-2026-74320)

Summary:	CVE-2026-74320 kernel: fbdev: sm501fb: Fix buffer errors in OF binding code
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability-draft	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	rhel-process-autobot, 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 `fbdev: sm501fb` component of the Linux kernel. The code responsible for obtaining frame buffer mode information from Open Firmware (OF) binding contains multiple memory handling errors. These include use-after-free vulnerabilities, buffer overruns when writing mode strings without proper length checks, and memory leaks. These issues could lead to system instability or potentially allow a local attacker to impact system integrity.	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 2026-08-15 06:35:30 UTC

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

fbdev: sm501fb: Fix buffer errors in OF binding code

The code that gets the frame buffer mode from OF has 'use after free',
'buffer overrun' and memory leaks.

info->edid_data isn't free if the probe functions fail or if
pd->def_mode is set.

If both the CRT and PANEL are enabled info->edid_data is used after
being freed and is freed twice.

The string returned by of_get_property(np, "mode", &len) is just
written over either the static "640x480-16@60" or the module parameter
string without any regard for the length (which is most likely longer).

Use kstrump() for the OF mode and free everything before freeing 'info.

Comment 1 gkamathe 2026-08-19 11:03:24 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081553-CVE-2026-74320-55ab@gregkh/T