Bug 2524506 (CVE-2026-80579)

Summary:	CVE-2026-80579 kernel: fbdev: clear fb_info->mode before deleting a videomode
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:	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 Linux kernel's `fbdev` component. A local user could exploit a use-after-free vulnerability by manipulating video modes. When a mode is deleted, the `fb_info->mode` pointer might not be cleared, leading to a stale pointer dereference during subsequent system file system (sysfs) reads. This could result in a denial of service.	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 2026-08-26 15:03:19 UTC

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

fbdev: clear fb_info->mode before deleting a videomode

fb_set_var() can delete a mode from info->modelist when userspace
passes FB_ACTIVATE_INV_MODE through FBIOPUT_VSCREENINFO. The code
checks that the mode being deleted is not the current info->var and
that fbcon is not using it, but it does not check fb_info->mode.

fb_info->mode may still point into the modelist entry being deleted.
If the entry is freed, later mode sysfs reads through show_mode() can
dereference a stale pointer.

Clear fb_info->mode before calling fb_delete_videomode() when it
matches the mode being removed.

Comment 1 gkamathe 2026-08-27 13:54:35 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026082614-CVE-2026-80579-33ae@gregkh/T