Heap Buffer Overflow Vulnerability in X.org X Server and XWayland
CVE-2026-93517

8.5HIGH

Key Information:

Vendor

X.orgg

Status
Xorg-x11-server
Xwayland
Vendor
CVE Published:
28 October 2026

What is CVE-2026-93517?

A heap buffer overflow vulnerability has been identified in the handling of GLX RenderLarge requests within the X.org X server and XWayland. When the dataBytes input parameter exceeds the cmdlen, it can be triggered by an authenticated X client. This flaw can potentially lead to crashes or allow for arbitrary code execution in the context of the X server. Users of affected versions must take immediate action to mitigate any risks associated with this vulnerability.

Affected Version(s)

xorg-x11-server 0 < 21.1.25

xwayland 0 < 24.1.14

References

https://gitlab.freedesktop.org/xorg/xserver/-/commit/2abe...
patch

CVSS V4

Score:
8.5
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Anonymous working with TrendAI Zero Day Initiative
.