Skip to content
fr Sign in
7.8 High

CVE-2026-50256 Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: stack buffer overflow in font alias resolution due to libxfont2 name length mismatch

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.

CVSS 3.1 detail

Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitable with local access to the machine, with an ordinary account and without any user action; an attacker can seriously compromise confidentiality, integrity or availability.

Attack vector
Local
Attack complexity
Low
Privileges required
Low
Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Affected products and versions

Product Affected versions Fixed in
Red Hat Enterprise Linux 10 Versions not published
Red Hat Enterprise Linux 6 Versions not published
Red Hat Enterprise Linux 7 Versions not published
Red Hat Enterprise Linux 8 Versions not published
Red Hat Enterprise Linux 9 Versions not published
Red Hat Enterprise Linux AppStream (v. 10) Versions not published
Red Hat Enterprise Linux AppStream (v. 8) Versions not published
Red Hat Enterprise Linux AppStream (v. 9) Versions not published
Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) Versions not published
Show the 28 other branches
Product Affected versions Fixed in
Red Hat Enterprise Linux CRB (v. 8) Versions not published
Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) Versions not published
Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions Versions not published
Red Hat Enterprise Linux Server (v. 7 ELS) Versions not published
Red Hat Enterprise Linux Server Optional (v. 7 ELS) Versions not published
Red Hat Enterprise Linux AppStream E4S (v.9.2) Versions not published
Red Hat Enterprise Linux AppStream E4S (v.9.4) Versions not published
Red Hat Enterprise Linux AppStream EUS (v.9.6) Versions not published
Red Hat CodeReady Linux Builder EUS (v.9.6) Versions not published
Red Hat Enterprise Linux 7 Extended Lifecycle Support Versions not published
Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions Versions not published
Red Hat Enterprise Linux 9.6 Extended Update Support Versions not published
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support Versions not published
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On Versions not published
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support Versions not published
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On Versions not published
Red Hat Enterprise Linux 10.0 Extended Update Support Versions not published
Red Hat Enterprise Linux 8.8 Telecommunications Update Service Versions not published
Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions Versions not published
Red Hat Enterprise Linux AppStream EUS (v. 10.0) Versions not published
Red Hat Enterprise Linux AppStream AUS (v.8.4) Versions not published
Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) Versions not published
Red Hat Enterprise Linux AppStream AUS (v.8.6) Versions not published
Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) Versions not published
Red Hat Enterprise Linux AppStream E4S (v.8.8) Versions not published
Red Hat Enterprise Linux AppStream TUS (v.8.8) Versions not published
Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) Versions not published
Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION Versions not published

References

Timeline

  1. Published
  2. Last modified

Other CVEs of Red Hat Enterprise Linux 10

The 1454 CVEs of Red Hat Enterprise Linux 10 →
CVE-2026-123151 Gdb: gdb: stack buffer overflow in parse_tsv_definition via stale rs->buf tail Not rated CVE-2026-121997 Gdb: gdbserver: heap buffer overflow in cmd_qtdpsrc via qtdpsrc declared/actual length mismatch 8.1 High CVE-2026-121996 Gdb: gdbserver: heap disclosure and wild pointer in gdb_parse_agent_expr via untrusted agent-expression length 8.2 High CVE-2026-121995 Gdb: gdb: stack buffer overflow in parse_tracepoint_definition via stale rs->buf tail 7.5 High
Track this CVE