Critical severity · published May 5, 2026
CVE-2026-34000
Xwayland: xorg: x.org x server: information disclosure and denial of service via out-of-bounds read in xkb geometry processing.
9.1
CVSS
0.5%
EPSS
No
On KEV
Description
A flaw was found in the X.Org X server. This out-of-bounds read vulnerability in the XKB geometry processing, specifically within the `CheckSetGeom()` and `XkbAddGeomKeyAlias` functions, allows an attacker to read uninitialized or out-of-bounds memory. An attacker with a connection to the X11 server, either locally or remotely, can exploit this without user interaction. This could lead to the disclosure of memory contents or cause a denial of service by crashing the server.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 42% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RH
Red Hat Enterprise Linux 10 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 10.0 Extended Update Support · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 6 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 7 Extended Lifecycle Support · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 8 · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 8.6 Telecommunications Update Service · Red Hat
All versions, or not specified · source: vendor
RH
Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions · Red Hat
All versions, or not specified · source: vendor
In the news
VulnerabilityMedium
ZDI-26-334: X.Org Server CheckSetGeom Out-Of-Bounds Read Information Disclosure Vulnerability
This vulnerability allows local attackers to disclose sensitive information on affected installations of X.Org Server. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The ZDI has assigned a CVSS rating of 6.1. The following CVEs are assigned: CVE-2026-34000.
Jun 9, 2026·Zero Day Initiative
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34000
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-34000
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:19342
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:20547
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:20555
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:20557
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:20558
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:20560
More from Red Hat Enterprise Linux 10
7.8
CVE-2026-31431
crypto: algif_aead - Revert to operating out-of-place
7.5
CVE-2026-34486
Apache Tomcat: Fix for CVE-2026-29146 allowed bypass of EncryptInterceptor
10.0
CVE-2026-46595
Invoking VerifiedPublicKeyCallback permissions skip enforcement in golang.org/x/crypto/ssh
10.0
CVE-2026-34078
Flatpak has a complete sandbox escape leading to host file access and code execution in the host context
10.0
CVE-2026-4692
Sandbox escape in the Responsive Design Mode component
