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CVE PROGRAM SOURCE RECORD7.8 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

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Status: Published
Published: 2026-06-05
Updated: 2026-09-28
Assigning organization: redhat

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Red Hat Red Hat Enterprise Linux 10

Default version status: affected

0:24.1.9-4.el10_2.2 to < *unaffected

Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support

Default version status: affected

0:24.1.5-6.el10_0.1 to < *unaffected

Red Hat Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION

Default version status: affected

0:1.1.0-25.el6_10.18 to < *unaffected

Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support

Default version status: affected

0:1.20.4-35.el7_9 to < *unaffected

Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support

Default version status: affected

0:1.8.0-36.el7_9.5 to < *unaffected

Red Hat Red Hat Enterprise Linux 8

Default version status: affected

0:21.1.3-20.el8_10.2 to < *unaffected

Red Hat Red Hat Enterprise Linux 8

Default version status: affected

0:1.20.11-28.el8_10.2 to < *unaffected

Red Hat Red Hat Enterprise Linux 8

Default version status: affected

0:1.15.0-10.el8_10 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support

Default version status: affected

0:1.20.10-5.el8_4 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support

Default version status: affected

0:1.11.0-8.el8_4.16 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

Default version status: affected

0:1.20.10-5.el8_4 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

Default version status: affected

0:1.11.0-8.el8_4.16 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support

Default version status: affected

0:1.20.11-8.el8_6 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support

Default version status: affected

0:21.1.3-2.el8_6.7 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support

Default version status: affected

0:1.12.0-6.el8_6.18 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On

Default version status: affected

0:1.20.11-8.el8_6 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On

Default version status: affected

0:21.1.3-2.el8_6.7 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On

Default version status: affected

0:1.12.0-6.el8_6.18 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service

Default version status: affected

0:1.20.11-19.el8_8 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service

Default version status: affected

0:21.1.3-13.el8_8.1 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service

Default version status: affected

0:1.12.0-15.el8_8.18 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions

Default version status: affected

0:1.20.11-19.el8_8 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions

Default version status: affected

0:21.1.3-13.el8_8.1 to < *unaffected

Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions

Default version status: affected

0:1.12.0-15.el8_8.18 to < *unaffected

Red Hat Red Hat Enterprise Linux 9

Default version status: affected

0:24.1.9-4.el9_8.2 to < *unaffected

Red Hat Red Hat Enterprise Linux 9

Default version status: affected

0:1.20.11-34.el9_8.2 to < *unaffected

Red Hat Red Hat Enterprise Linux 9

Default version status: affected

0:1.15.0-7.el9_8.2 to < *unaffected

Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Default version status: affected

0:1.20.11-21.el9_2 to < *unaffected

Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Default version status: affected

0:21.1.3-10.el9_2.1 to < *unaffected

Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Default version status: affected

0:1.12.0-14.el9_2.15 to < *unaffected

Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions

Default version status: affected

0:1.20.11-29.el9_4 to < *unaffected

Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions

Default version status: affected

0:22.1.9-8.el9_4.1 to < *unaffected

Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions

Default version status: affected

0:1.13.1-8.el9_4.10 to < *unaffected

Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support

Default version status: affected

0:1.20.11-34.el9_6 to < *unaffected

Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support

Default version status: affected

0:23.2.7-6.el9_6.1 to < *unaffected

Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support

Default version status: affected

0:1.14.1-11.el9_6 to < *unaffected

Red Hat Red Hat Enterprise Linux 6

Default version status: unknown

References