xorg-server / xwayland glamor font atlas Heap Buffer Overflow

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Summary

CVECVE-2026-55999
StatePUBLISHED
Assignersuse
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-08 09:16:29 UTC
Updated2026-07-09 16:39:17 UTC
DescriptionLocal 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.

Risk And Classification

Primary CVSS: v3.1 8.5 HIGH from [email protected]

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

EPSS: 0.002840000 probability, percentile 0.202650000 (date 2026-07-08)

Problem Types: CWE-122 | CWE-122 CWE-122 Heap-based buffer overflow

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary8.5HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
3.1CNACVSS8.5HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA X.Org Xorg-server affected 21.1.24 rpm Not specified
CNA X.Org Xwayland affected 24.1.13 rpm Not specified

References

ReferenceSourceLinkTags
www.openwall.com/lists/oss-security/2026/07/08/2 [email protected] www.openwall.com
gitlab.freedesktop.org/xorg/xserver/-/commit/fbf7bac22e2c6bd627fb042742a23318263edae1 [email protected] gitlab.freedesktop.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Anonymous working with Trend Micro Zero Day Initiative. (en)

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