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CVE-2026-50256

A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland.

Impact

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 products

VendorProductAffected versions
X.OrgX Server
before 21.1.23
X.OrgXwayland
before 24.1.12
RedhatEnterprise Linux
Versions 7.0, 8.0, 9.0, 10.0

Weakness classification

CWE-121

References