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
A stack-based buffer overflow exists in the X.Org X server and Xwayland within Red Hat Enterprise Linux 10 due to the function _XkbSetMapChecks() declaring 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 can cause the X server to crash or potentially allow privilege escalation when the server operates as root. The vulnerability is tracked as CVE-2026-50259 with a CVSS 3.1 score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
Potential Impact
Successful exploitation may cause denial of service by crashing the X server or enable privilege escalation if the X server is running with root privileges, potentially compromising system confidentiality, integrity, and availability. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-50259 for current remediation guidance. Until an official fix is available, consider limiting access to the X server and running it with the least privileges possible to reduce risk.
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
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
A stack-based buffer overflow exists in the X.Org X server and Xwayland within Red Hat Enterprise Linux 10 due to the function _XkbSetMapChecks() declaring 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 can cause the X server to crash or potentially allow privilege escalation when the server operates as root. The vulnerability is tracked as CVE-2026-50259 with a CVSS 3.1 score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
Potential Impact
Successful exploitation may cause denial of service by crashing the X server or enable privilege escalation if the X server is running with root privileges, potentially compromising system confidentiality, integrity, and availability. There are no known exploits in the wild at this time.
Mitigation Recommendations
Patch status is not yet confirmed — check the Red Hat advisory at https://access.redhat.com/security/cve/CVE-2026-50259 for current remediation guidance. Until an official fix is available, consider limiting access to the X server and running it with the least privileges possible to reduce risk.
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: 6/5/2026, 11:48:40 AM
Last enriched: 6/5/2026, 12:03:41 PM
Last updated: 6/6/2026, 6:01:15 AM
Views: 12
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