CVE-2026-50256: Stack-based Buffer Overflow in Red Hat Red Hat Enterprise Linux 10
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.
AI Analysis
Technical Summary
This advisory covers multiple security flaws in the xorg-x11-server-Xwayland component, part of the TigerVNC suite and Red Hat Enterprise Linux distributions. The vulnerabilities include stack buffer overflows caused by unchecked input lengths and indexing, use-after-free bugs in several functions, and out-of-bounds read/write conditions. These issues could lead to memory corruption and potential information disclosure. Red Hat has released updates for affected versions to remediate these vulnerabilities.
Potential Impact
The vulnerabilities can cause memory corruption through stack buffer overflows and use-after-free conditions, potentially leading to denial of service or information disclosure. The issues affect the X server running under Wayland (Xwayland), which is used to run X clients in Wayland environments. Exploitation could impact systems running vulnerable versions of Red Hat Enterprise Linux and TigerVNC, especially those using Xwayland for remote desktop functionality.
Mitigation Recommendations
Red Hat has released official security updates addressing these vulnerabilities. Users should apply the provided patches and updates for xorg-x11-server-Xwayland and TigerVNC as detailed in the Red Hat advisories RHSA-2026:26562 and RHSA-2026:49519. No additional mitigation steps are indicated beyond applying these updates.
CVE-2026-50256: Stack-based Buffer Overflow in Red Hat Red Hat Enterprise Linux 10
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 v3.1
Score 7.8high
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This advisory covers multiple security flaws in the xorg-x11-server-Xwayland component, part of the TigerVNC suite and Red Hat Enterprise Linux distributions. The vulnerabilities include stack buffer overflows caused by unchecked input lengths and indexing, use-after-free bugs in several functions, and out-of-bounds read/write conditions. These issues could lead to memory corruption and potential information disclosure. Red Hat has released updates for affected versions to remediate these vulnerabilities.
Potential Impact
The vulnerabilities can cause memory corruption through stack buffer overflows and use-after-free conditions, potentially leading to denial of service or information disclosure. The issues affect the X server running under Wayland (Xwayland), which is used to run X clients in Wayland environments. Exploitation could impact systems running vulnerable versions of Red Hat Enterprise Linux and TigerVNC, especially those using Xwayland for remote desktop functionality.
Mitigation Recommendations
Red Hat has released official security updates addressing these vulnerabilities. Users should apply the provided patches and updates for xorg-x11-server-Xwayland and TigerVNC as detailed in the Red Hat advisories RHSA-2026:26562 and RHSA-2026:49519. No additional mitigation steps are indicated beyond applying these updates.
Technical Details
- Gcve Source
- db.gcve.eu
- Csaf Category
- csaf_security_advisory
- Csaf Version
- 2.0
- Publisher
- Red Hat Product Security
- Advisory Id
- RHSA-2026:26562
- Cve Count
- 9
- Additional Cves
- ["CVE-2026-50257","CVE-2026-50258","CVE-2026-50259","CVE-2026-50260","CVE-2026-50261","CVE-2026-50262","CVE-2026-50263","CVE-2026-50264"]
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a32cef49f87a2db092a2a2f
Added to database: 06/17/2026, 16:44:36 UTC
Last enriched: 08/03/2026, 23:18:53 UTC
Last updated: 09/13/2026, 22:01:34 UTC
Views: 108
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