AI description
Automated description summarized from trusted sources.
CVE-2026-50256 describes a stack-based buffer overflow vulnerability affecting the X.Org X server and Xwayland. This flaw stems from a discrepancy in buffer sizes during font alias resolution. Specifically, the X server allocates a 256-byte stack buffer for font alias names, while the `libXfont2` library can handle alias target names up to 1024 bytes. When a font alias name falls between 257 and 1023 bytes in length, the X server attempts to copy this name into its undersized 256-byte buffer without proper bounds checking. This action leads to a stack buffer overflow. The vulnerability could potentially be exploited to crash the server or, in scenarios where the X server operates with root privileges, facilitate privilege escalation.
- 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
- secalert@redhat.com
- NVD status
- Modified
- Products
- x_server, xwayland, enterprise_linux
CVSS 3.1
- Type
- Secondary
- Base score
- 7.8
- Impact score
- 5.9
- Exploitability score
- 1.8
- Vector string
- CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Severity
- HIGH
- Hype score
- Not currently trending
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