CVE-2026-55999 PUBLISHED

xorg-server / xwayland glamor font atlas Heap Buffer Overflow

Assigner: suse
Reserved: 18.06.2026 Published: 08.07.2026 Updated: 08.07.2026

Local attackers with a X connection able to provide PCX fonts to the X server xorg-server before 21.2.24 and xwayland before 24.1.13 could cause a heap buffer overflow via SetFont due to missing glyph boundary checks.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS Score: 8.5

Attack Vector	Network	Scope	Changed
Attack Complexity	High	Confidentiality Impact	High
Privileges Required	Low	Integrity Impact	High
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	X.Org
Product	xorg-server
Versions	Default: unaffected affected from 0 to 21.1.24 (excl.)

Vendor	X.Org
Product	xwayland
Versions	Default: unaffected affected from 0 to 24.1.13 (excl.)

Credits

Anonymous working with Trend Micro Zero Day Initiative. finder

References

Problem Types

CWE-122 Heap-based buffer overflow CWE

Impacts

CAPEC-234 Hijacking a privileged process