Bug 2555545

Summary: CVE-2026-93522 xorg-x11-server-Xwayland: glamor: size tmp_bits buffer for source coordinate range in upload_boxes [fedora-all]
Product: [Fedora] Fedora Reporter: Marian Rehak <mrehak>
Component: xorg-x11-server-XwaylandAssignee: Olivier Fourdan <ofourdan>
Status: CLOSED CURRENTRELEASE QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: rawhideCC: mdaenzer, ofourdan, suraj.ghimire7
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["05ea0549-d959-4d39-99af-a188041fd15a"]}
Fixed In Version: Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-10-19 12:17:37 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2545178    

Description Marian Rehak 2026-10-19 11:15:17 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

glamor_upload_boxes() allocates the tmp_bits buffer (used for 24-bit to
32-bit depth conversion) based on the destination pixmap height, but
indexes it using source coordinates (y1 - dy_dst + dy_src). When the
source is taller than the destination, the source-relative offset
exceeds the destination height, causing writes past the buffer end.

Size the buffer to account for the source coordinate mapping:
byte_stride * (pixmap->drawable.height - dy_dst + dy_src). This
ensures the buffer covers the full range of source rows that will be
accessed during the upload.

This vulnerability was discovered by:
  Anonymous working with TrendAI Zero Day Initiative

ZDI-CAN-32361
Comment 1 Olivier Fourdan 2026-10-19 12:17:09 UTC 
The following security issues:
* CVE-2026-88812
* CVE-2026-93515
* CVE-2026-93516
* CVE-2026-93517
* CVE-2026-93518
* CVE-2026-93519
* CVE-2026-93520
* CVE-2026-93521
* CVE-2026-93522
* CVE-2026-93523
* CVE-2026-93524
* CVE-2026-93536

Are addressed with the following updates already:
* https://bodhi.fedoraproject.org/updates/FEDORA-2026-12d1e72dfb
* https://bodhi.fedoraproject.org/updates/FEDORA-2026-2460ebb288
* https://bodhi.fedoraproject.org/updates/FEDORA-2026-2448dda850
* https://bodhi.fedoraproject.org/updates/FEDORA-2026-112c430ffc