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.
References
| Link | Resource |
|---|---|
| https://access.redhat.com/security/cve/CVE-2026-50256 | Vendor Advisory |
| https://bugzilla.redhat.com/show_bug.cgi?id=2485380 | Issue Tracking Vendor Advisory |
| https://gitlab.freedesktop.org/xorg/xserver/-/commit/bb5158f962dc935e58ef8b4b5fcb31be201a6e07 | Patch |
| https://lists.x.org/archives/xorg-announce/2026-June/003702.html | Mailing List Third Party Advisory |
| https://redhat.atlassian.net/browse/PSIRTSUPT-16950 | Permissions Required |
Configurations
Configuration 1 (hide)
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History
08 Jun 2026, 16:45
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://access.redhat.com/security/cve/CVE-2026-50256 - Vendor Advisory | |
| References | () https://bugzilla.redhat.com/show_bug.cgi?id=2485380 - Issue Tracking, Vendor Advisory | |
| References | () https://gitlab.freedesktop.org/xorg/xserver/-/commit/bb5158f962dc935e58ef8b4b5fcb31be201a6e07 - Patch | |
| References | () https://lists.x.org/archives/xorg-announce/2026-June/003702.html - Mailing List, Third Party Advisory | |
| References | () https://redhat.atlassian.net/browse/PSIRTSUPT-16950 - Permissions Required | |
| First Time |
Redhat enterprise Linux
Redhat X.org X.org xwayland X.org x Server |
|
| CPE | cpe:2.3:a:x.org:xwayland:*:*:*:*:*:*:*:* cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:* cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:* cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:* cpe:2.3:a:x.org:x_server:*:*:*:*:*:*:*:* cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:* |
05 Jun 2026, 12:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-06-05 12:16
Updated : 2026-06-08 16:45
NVD link : CVE-2026-50256
Mitre link : CVE-2026-50256
CVE.ORG link : CVE-2026-50256
JSON object : View
Products Affected
x.org
- x_server
- xwayland
redhat
- enterprise_linux
CWE
CWE-121
Stack-based Buffer Overflow