Strix
26.1K

CVE-2026-50259

HIGHCVSS 7.8/10EPSS 0.16%

Last modified

CVE-2026-50259 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. 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. EPSS estimates a 0.16% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.16%

5.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
X.OrgX Server< 21.1.23
X.OrgXwayland< 24.1.12
RedhatEnterprise Linux7.0
RedhatEnterprise Linux8.0
RedhatEnterprise Linux9.0
RedhatEnterprise Linux10.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2026-50259?
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.
How severe is CVE-2026-50259?
CVE-2026-50259 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.16% probability of exploitation in the next 30 days.
How do I fix CVE-2026-50259?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-50259?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST