🛡️ UBUNTU-CVE-2026-50256
⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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.

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-06-05
Updated 2026-06-13
Modified 2026-06-12
Fix URL N/A

Affected Packages

Software From version Fixed in
xorg-server — —
xorg-server-hwe-16.04 — —
xorg-server-hwe-18.04 — —
xwayland — —

Patch Gap Protection

Running software with known vulnerabilities?

BotEraser can help reduce exposure by blocking IPs associated with exploit activity — even before a patch is available.

Start Free →

No credit card required  ·  Results in minutes

ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.