Bug 2482635 (CVE-2026-46191)

Summary: CVE-2026-46191 kernel: fbcon: Avoid OOB font access if console rotation fails
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: 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 framebuffer console (fbcon) component. When console rotation fails, the `fbcon_rotate_font()` function may keep an old font buffer that is too small for the rotated font. A local user printing to the rotated console with a high character code can trigger an out-of-bounds write, leading to memory corruption. This can result in system instability or 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 2026-05-28 11:06:56 UTC 
In the Linux kernel, the following vulnerability has been resolved:

fbcon: Avoid OOB font access if console rotation fails

Clear the font buffer if the reallocation during console rotation fails
in fbcon_rotate_font(). The putcs implementations for the rotated buffer
will return early in this case. See [1] for an example.

Currently, fbcon_rotate_font() keeps the old buffer, which is too small
for the rotated font. Printing to the rotated console with a high-enough
character code will overflow the font buffer.

v2:
- fix typos in commit message
Comment 1 Keith Grant 2026-05-28 14:05:04 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026052832-CVE-2026-46191-012c@gregkh/T