CVE-2026-50256
7.8 HIGHA stack-based buffer overflow flaw was found in the X.Org X server and Xwayland
Published: 2026-06-05 · Last updated: 2026-06-08
Severity and scoring
- CVSS
- 7.8 HIGH
- Vector
- CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CWE
- CWE-121
Affected products
| Vendor | Product |
|---|---|
| redhat | enterprise_linux, x_server, xwayland |
| x.org | enterprise_linux, x_server, xwayland |
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.
Source: NVD
References
- [NVD]https://nvd.nist.gov/vuln/detail/CVE-2026-50256
- [Vendor advisory]https://access.redhat.com/security/cve/CVE-2026-50256
- [Vendor advisory]https://bugzilla.redhat.com/show_bug.cgi?id=2485380
- [Patch]https://gitlab.freedesktop.org/xorg/xserver/-/commit/bb5158f962dc935e58ef8b4b5fcb31be201a6e07
- [Other]https://lists.x.org/archives/xorg-announce/2026-June/003702.html
- [Other]https://redhat.atlassian.net/browse/PSIRTSUPT-16950
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