XKB Modmap OOB Read in X.Org X Server
CVE-2026-34002 Published on May 5, 2026

Xorg: xwayland: x.org x server: information disclosure or denial of service via out-of-bounds read in xkb modifier map handling
A flaw was found in the X.Org X server. This vulnerability, an out-of-bounds read, affects the XKB (X Keyboard Extension) modifier map handling. An attacker with access to the X11 server can exploit this by sending a malformed request, which causes the server to read beyond its intended memory boundaries. This can lead to the exposure of sensitive information or cause the server to crash, resulting in a denial of service.

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Vulnerability Analysis

CVE-2026-34002 is exploitable with local system access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity, and a small impact on availability.

Attack Vector:
LOCAL
Attack Complexity:
LOW
Privileges Required:
LOW
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
NONE
Availability Impact:
LOW

Timeline

Reported to Red Hat.

Made public. 41 days later.

Weakness Type

Buffer Access with Incorrect Length Value

The software uses a sequential operation to read or write a buffer, but it uses an incorrect length value that causes it to access memory that is outside of the bounds of the buffer. When the length value exceeds the size of the destination, a buffer overflow could occur.


Products Associated with CVE-2026-34002

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Red Hat Enterprise Linux (RHEL)
 
Red Hat Rhel E4s
 
Red Hat Rhel Eus
 
Red Hat Enterprise Linux Eus
 
Red Hat Rhel Els
 
Red Hat Rhel Aus
 
Red Hat Rhel Tus
 
Red Hat Rhel Eus Long Life
 

Affected Versions

Red Hat Enterprise Linux 10.0 Extended Update Support: Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION: Red Hat Enterprise Linux 7 Extended Lifecycle Support: Red Hat Enterprise Linux 7 Extended Lifecycle Support: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support: Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On: Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On: Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support: Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support: Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support: Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On: Red Hat Enterprise Linux 8.6 Telecommunications Update Service: Red Hat Enterprise Linux 8.6 Telecommunications Update Service: Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions: Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions: Red Hat Enterprise Linux 8.8 Telecommunications Update Service: Red Hat Enterprise Linux 8.8 Telecommunications Update Service: Red Hat Enterprise Linux 8.8 Telecommunications Update Service: Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions: Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions: Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.4 Extended Update Support: Red Hat Enterprise Linux 9.4 Extended Update Support: Red Hat Enterprise Linux 9.4 Extended Update Support: Red Hat Enterprise Linux 9.6 Extended Update Support: Red Hat Enterprise Linux 9.6 Extended Update Support: Red Hat Enterprise Linux 9.6 Extended Update Support: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 6: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9:

Exploit Probability

EPSS
0.03%
Percentile
9.59%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.