CVE-2026-50259: 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. _XkbSetMapChecks() declares a fixed-size stack buffer mapWidths[256] indexed by key type index. The helper function CheckKeyTypes() writes to this buffer at a client-controlled offset, allowing a stack buffer overflow. This may be used to crash the server, or for privilege escalation if the X server runs as root.
AI Analysis
Technical Summary
CVE-2026-50259 is a stack-based buffer overflow vulnerability in the X.Org X server and Xwayland, specifically in the _XkbSetMapChecks() function which declares a fixed-size stack buffer mapWidths[256]. The helper function CheckKeyTypes() writes to this buffer using a client-controlled index, enabling a stack buffer overflow. This vulnerability can cause denial of service via server crashes or privilege escalation when the X server operates as root. Red Hat has issued security advisories (RHSA-2026:26562 for RHEL 8 and RHSA-2026:26566 for RHEL 10) providing patches that fix this and several other related vulnerabilities in the xorg-x11-server and xorg-x11-server-Xwayland packages.
Potential Impact
Successful exploitation of this vulnerability may allow an attacker to cause a denial of service by crashing the X server or escalate privileges if the X server is running with root privileges. The CVSS 3.1 base score is 7.8 (High), reflecting the potential for high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
Red Hat has released official security updates that address CVE-2026-50259. Users of affected Red Hat Enterprise Linux versions should apply the updated xorg-x11-server and xorg-x11-server-Xwayland packages as detailed in Red Hat advisories RHSA-2026:26562 and RHSA-2026:26566. Patch application is the recommended mitigation. No additional vendor-stated mitigations or workarounds are noted.
CVE-2026-50259: 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. _XkbSetMapChecks() declares a fixed-size stack buffer mapWidths[256] indexed by key type index. The helper function CheckKeyTypes() writes to this buffer at a client-controlled offset, allowing a stack buffer overflow. 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
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-50259 is a stack-based buffer overflow vulnerability in the X.Org X server and Xwayland, specifically in the _XkbSetMapChecks() function which declares a fixed-size stack buffer mapWidths[256]. The helper function CheckKeyTypes() writes to this buffer using a client-controlled index, enabling a stack buffer overflow. This vulnerability can cause denial of service via server crashes or privilege escalation when the X server operates as root. Red Hat has issued security advisories (RHSA-2026:26562 for RHEL 8 and RHSA-2026:26566 for RHEL 10) providing patches that fix this and several other related vulnerabilities in the xorg-x11-server and xorg-x11-server-Xwayland packages.
Potential Impact
Successful exploitation of this vulnerability may allow an attacker to cause a denial of service by crashing the X server or escalate privileges if the X server is running with root privileges. The CVSS 3.1 base score is 7.8 (High), reflecting the potential for high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
Red Hat has released official security updates that address CVE-2026-50259. Users of affected Red Hat Enterprise Linux versions should apply the updated xorg-x11-server and xorg-x11-server-Xwayland packages as detailed in Red Hat advisories RHSA-2026:26562 and RHSA-2026:26566. Patch application is the recommended mitigation. No additional vendor-stated mitigations or workarounds are noted.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- redhat
- Date Reserved
- 2026-06-04T14:55:24.011Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-50259","vendor":"Red Hat"}]
Threat ID: 6a22b798e29bf47b506379f2
Added to database: 06/05/2026, 11:48:40 UTC
Last enriched: 07/30/2026, 00:07:11 UTC
Last updated: 07/31/2026, 21:26:47 UTC
Views: 90
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