CVE-2026-50259

high

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.

References

https://lists.x.org/archives/xorg-announce/2026-June/003702.html

https://bugzilla.redhat.com/show_bug.cgi?id=2485384

https://access.redhat.com/security/cve/CVE-2026-50259

https://access.redhat.com/errata/RHSA-2026:49519

https://access.redhat.com/errata/RHSA-2026:46473

https://access.redhat.com/errata/RHSA-2026:46460

https://access.redhat.com/errata/RHSA-2026:46456

https://access.redhat.com/errata/RHSA-2026:46392

https://access.redhat.com/errata/RHSA-2026:46385

https://access.redhat.com/errata/RHSA-2026:46382

https://access.redhat.com/errata/RHSA-2026:46377

https://access.redhat.com/errata/RHSA-2026:38810

https://access.redhat.com/errata/RHSA-2026:38502

https://access.redhat.com/errata/RHSA-2026:36798

https://access.redhat.com/errata/RHSA-2026:36792

https://access.redhat.com/errata/RHSA-2026:36791

https://access.redhat.com/errata/RHSA-2026:36768

https://access.redhat.com/errata/RHSA-2026:36634

https://access.redhat.com/errata/RHSA-2026:36633

https://access.redhat.com/errata/RHSA-2026:36632

https://access.redhat.com/errata/RHSA-2026:36087

https://access.redhat.com/errata/RHSA-2026:36086

https://access.redhat.com/errata/RHSA-2026:36085

https://access.redhat.com/errata/RHSA-2026:36083

https://access.redhat.com/errata/RHSA-2026:29844

https://access.redhat.com/errata/RHSA-2026:28923

https://access.redhat.com/errata/RHSA-2026:26709

https://access.redhat.com/errata/RHSA-2026:26610

https://access.redhat.com/errata/RHSA-2026:26590

https://access.redhat.com/errata/RHSA-2026:26566

https://access.redhat.com/errata/RHSA-2026:26562

Details

Source: Mitre, NVD

Published: 2026-06-05

Updated: 2026-08-05

Risk Information

CVSS v2

Base Score: 6.8

Vector: CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C

Severity: Medium

CVSS v3

Base Score: 7.8

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

Severity: High

EPSS

EPSS: 0.00012