CVE-2026-33999

Xorg: xwayland: x.org x server: denial of service via integer underflow in xkb compatibility map handling

State: Published
Severity: 7.8 High
Published: Apr 23, 2026
Updated: Jul 15, 2026
Reserved: Mar 25, 2026

Description

A flaw was found in the X.Org X server. This integer underflow vulnerability, specifically in the XKB compatibility map handling, allows an attacker with local or remote X11 server access to trigger a buffer read overrun. This can lead to memory-safety violations and potentially a denial of service (DoS) or other severe impacts.

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	redhat
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	redhat-SADP

Weaknesses

CWE-191 Integer Underflow (Wrap or Wraparound)

Affected Products

Product	Versions
Red Hat Enterprise Linux 10Red Hat	0:24.1.5-6.el10_1 and laterNot affected
Red Hat Enterprise Linux 10Red Hat	0:24.1.9-4.el10_2 and laterNot affected
Red Hat Enterprise Linux 10.0 Extended Update SupportRed Hat	0:24.1.5-6.el10_0 and laterNot affected
Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSIONRed Hat	0:1.1.0-25.el6_10.16 and laterNot affected
Red Hat Enterprise Linux 7 Extended Lifecycle SupportRed Hat	0:1.20.4-34.el7_9 and laterNot affected
Red Hat Enterprise Linux 7 Extended Lifecycle SupportRed Hat	0:1.8.0-36.el7_9.4 and laterNot affected
Red Hat Enterprise Linux 8Red Hat	0:21.1.3-20.el8_10 and laterNot affected
Red Hat Enterprise Linux 8Red Hat	0:1.20.11-28.el8_10 and laterNot affected
Red Hat Enterprise Linux 8Red Hat	0:1.15.0-9.el8_10 and laterNot affected
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update SupportRed Hat	0:1.20.10-4.el8_4 and laterNot affected
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update SupportRed Hat	0:1.11.0-8.el8_4.15 and laterNot affected
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-OnRed Hat	0:1.20.10-4.el8_4 and laterNot affected
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-OnRed Hat	0:1.11.0-8.el8_4.15 and laterNot affected
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update SupportRed Hat	0:21.1.3-2.el8_6.6 and laterNot affected
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update SupportRed Hat	0:1.20.11-7.el8_6 and laterNot affected
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update SupportRed Hat	0:1.12.0-6.el8_6.17 and laterNot affected
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-OnRed Hat	0:1.12.0-6.el8_6.17 and laterNot affected
Red Hat Enterprise Linux 8.6 Telecommunications Update ServiceRed Hat	0:21.1.3-2.el8_6.6 and laterNot affected
Red Hat Enterprise Linux 8.6 Telecommunications Update ServiceRed Hat	0:1.20.11-7.el8_6 and laterNot affected
Red Hat Enterprise Linux 8.6 Update Services for SAP SolutionsRed Hat	0:21.1.3-2.el8_6.6 and laterNot affected
Red Hat Enterprise Linux 8.6 Update Services for SAP SolutionsRed Hat	0:1.20.11-7.el8_6 and laterNot affected
Red Hat Enterprise Linux 8.8 Telecommunications Update ServiceRed Hat	0:21.1.3-13.el8_8 and laterNot affected
Red Hat Enterprise Linux 8.8 Telecommunications Update ServiceRed Hat	0:1.20.11-18.el8_8 and laterNot affected
Red Hat Enterprise Linux 8.8 Telecommunications Update ServiceRed Hat	0:1.12.0-15.el8_8.17 and laterNot affected
Red Hat Enterprise Linux 8.8 Update Services for SAP SolutionsRed Hat	0:21.1.3-13.el8_8 and laterNot affected
Red Hat Enterprise Linux 8.8 Update Services for SAP SolutionsRed Hat	0:1.20.11-18.el8_8 and laterNot affected
Red Hat Enterprise Linux 8.8 Update Services for SAP SolutionsRed Hat	0:1.12.0-15.el8_8.17 and laterNot affected
Red Hat Enterprise Linux 9Red Hat	0:1.15.0-6.el9_7.1 and laterNot affected
Red Hat Enterprise Linux 9Red Hat	0:23.2.7-6.el9_7 and laterNot affected
Red Hat Enterprise Linux 9Red Hat	0:1.20.11-33.el9_7 and laterNot affected
Red Hat Enterprise Linux 9Red Hat	0:1.15.0-7.el9_8.1 and laterNot affected
Red Hat Enterprise Linux 9Red Hat	0:1.20.11-34.el9_8 and laterNot affected
Red Hat Enterprise Linux 9Red Hat	0:24.1.9-4.el9_8 and laterNot affected
Red Hat Enterprise Linux 9.0 Update Services for SAP SolutionsRed Hat	0:21.1.3-5.el9_0 and laterNot affected
Red Hat Enterprise Linux 9.0 Update Services for SAP SolutionsRed Hat	0:1.20.11-13.el9_0 and laterNot affected
Red Hat Enterprise Linux 9.0 Update Services for SAP SolutionsRed Hat	0:1.11.0-22.el9_0.17 and laterNot affected
Red Hat Enterprise Linux 9.2 Update Services for SAP SolutionsRed Hat	0:21.1.3-10.el9_2 and laterNot affected
Red Hat Enterprise Linux 9.2 Update Services for SAP SolutionsRed Hat	0:1.20.11-20.el9_2 and laterNot affected
Red Hat Enterprise Linux 9.2 Update Services for SAP SolutionsRed Hat	0:1.12.0-14.el9_2.14 and laterNot affected
Red Hat Enterprise Linux 9.4 Extended Update SupportRed Hat	0:1.20.11-28.el9_4 and laterNot affected
Red Hat Enterprise Linux 9.4 Extended Update SupportRed Hat	0:22.1.9-8.el9_4 and laterNot affected
Red Hat Enterprise Linux 9.4 Extended Update SupportRed Hat	0:1.13.1-8.el9_4.9 and laterNot affected
Red Hat Enterprise Linux 9.6 Extended Update SupportRed Hat	0:1.20.11-33.el9_6 and laterNot affected
Red Hat Enterprise Linux 9.6 Extended Update SupportRed Hat	0:23.2.7-6.el9_6 and laterNot affected
Red Hat Enterprise Linux 9.6 Extended Update SupportRed Hat	0:1.14.1-10.el9_6 and laterNot affected
Red Hat Enterprise Linux 6Red Hat

References

RHSA-2026:10739vendor-advisory
RHSA-2026:11352vendor-advisory
RHSA-2026:11369vendor-advisory
RHSA-2026:11388vendor-advisory
RHSA-2026:11656vendor-advisory
RHSA-2026:11692vendor-advisory
RHSA-2026:13414vendor-advisory
RHSA-2026:19125vendor-advisory
RHSA-2026:19342vendor-advisory
RHSA-2026:19343vendor-advisory
RHSA-2026:19344vendor-advisory
RHSA-2026:20547vendor-advisory
RHSA-2026:20555vendor-advisory
RHSA-2026:20557vendor-advisory
RHSA-2026:20558vendor-advisory
RHSA-2026:20560vendor-advisory
RHSA-2026:20561vendor-advisory
RHSA-2026:20562vendor-advisory
RHSA-2026:20563vendor-advisory
RHSA-2026:20575vendor-advisory
RHSA-2026:20576vendor-advisory
RHSA-2026:20590vendor-advisory
RHSA-2026:21699vendor-advisory
RHSA-2026:21712vendor-advisory
RHSA-2026:21715vendor-advisory
RHSA-2026:21716vendor-advisory
RHSA-2026:21718vendor-advisory
RHSA-2026:21741vendor-advisory
RHSA-2026:21742vendor-advisory
RHSA-2026:22424vendor-advisory
RHSA-2026:22456vendor-advisory
RHSA-2026:23254vendor-advisory
RHSA-2026:23255vendor-advisory
RHSA-2026:23496vendor-advisory
RHSA-2026:24341vendor-advisory
https://access.redhat.com/security/cve/CVE-2026-33999vdb-entry
RHBZ#2451106issue-tracking
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33999.json

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