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HIGH · 8.5

CVE-2026-55999

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 gly...

Vulnerability Description

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.

CVSS Score

8.5

HIGH

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH

Affected Products

VendorProductVersions
X.OrgX Server< 21.2.24
X.OrgXwayland< 24.1.13

Related Weaknesses (CWE)

CWE-122

References

FAQ

What is CVE-2026-55999?

CVE-2026-55999 is a vulnerability with a CVSS score of 8.5 (HIGH). 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 gly...

How severe is CVE-2026-55999?

CVE-2026-55999 has been rated HIGH with a CVSS base score of 8.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-55999?

Check the references section above for vendor advisories and patch information. Affected products include: X.Org X Server, X.Org Xwayland.