Cloudanix VulnDB

CVE-2026-50256

High · 7.8

CVSS

7.8

EPSS

0.2%

Published

Jun 5, 2026

CISA due date

—

The record

A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. A mismatch between the X server and the libXfont2 library's maximum font name length can cause a stack buffer overflow during font alias resolution. The server allocates a 256 byte stack buffer but libXfont2's alias target name length is 1024 bytes. A font alias name between 257 and 1023 bytes causes the X server to copy that name into the undersized stack buffer without further checks. This may be used to crash the server, or for privilege escalation if the X server runs as root.

Affected packages

Ecosystem Package Introduced Fixed

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