7.8

CVE-2026-50258

Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: stack buffer overflow in xkb key types due to unchecked shift levels

A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. The X server has multiple stack buffers sized XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify or clamp non-canonical key types to XkbMaxShiftLevel. A client can change key types to excessive shift levels and trigger stack overflows. This is caused by an incomplete fix of CVE-2025-26597. This may be used to crash the server, or for privilege escalation if the X server runs as root.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
X.Org ≫ X Server Version < 21.1.23
X.Org ≫ Xwayland Version < 24.1.12
Redhat ≫ Enterprise Linux Version7.0
Redhat ≫ Enterprise Linux Version8.0
Redhat ≫ Enterprise Linux Version9.0
Redhat ≫ Enterprise Linux Version10.0
Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.16% 0.057
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
secalert@redhat.com 7.8 1.8 5.9
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
0b0ca135-0b70-47e7-9f44-1890c2a1c46c 7.8 1.8 5.9
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE-121 Stack-based Buffer Overflow

A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).

https://bugzilla.redhat.com/show_bug.cgi?id=2485383
Third Party Advisory
Issue Tracking
https://gitlab.freedesktop.org/xorg/xserver/-/commit/543e108516428fc8c3bea91d6563ad266f9a801e
Patch
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-50258.json
https://access.redhat.com/errata/RHSA-2026:26562
https://access.redhat.com/errata/RHSA-2026:26566
https://access.redhat.com/errata/RHSA-2026:26590
https://access.redhat.com/errata/RHSA-2026:26610
https://access.redhat.com/errata/RHSA-2026:26709
https://access.redhat.com/errata/RHSA-2026:28923
https://access.redhat.com/errata/RHSA-2026:29844
https://access.redhat.com/errata/RHSA-2026:36083
https://access.redhat.com/errata/RHSA-2026:36085
https://access.redhat.com/errata/RHSA-2026:36086
https://access.redhat.com/errata/RHSA-2026:36087
https://lists.x.org/archives/xorg-announce/2026-June/003702.html
Third Party Advisory
Mailing List
https://redhat.atlassian.net/browse/PSIRTSUPT-16950
Permissions Required
https://access.redhat.com/security/cve/CVE-2026-50258
Third Party Advisory
https://access.redhat.com/errata/RHSA-2026:36632
https://access.redhat.com/errata/RHSA-2026:36633
https://access.redhat.com/errata/RHSA-2026:36634
https://access.redhat.com/errata/RHSA-2026:36791
https://access.redhat.com/errata/RHSA-2026:36792
https://access.redhat.com/errata/RHSA-2026:36768
https://access.redhat.com/errata/RHSA-2026:36798