Cyber Posture

CVE-2025-26597

High

Published: 25 February 2025

Published
25 February 2025
Modified
06 April 2026
KEV Added
Patch
CVSS Score 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0003 8.1th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Description

Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.

Security Summary

CVE-2025-26597 is a buffer overflow vulnerability in X.Org and Xwayland. The flaw occurs in the XkbChangeTypesOfKey() function: when called with a group value of 0, it resizes the key symbols table to zero while leaving the key actions unchanged. A subsequent call with a non-zero group value then triggers a buffer overflow due to the mismatched size of the key actions table. This issue, classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), received a CVSS v3.1 base score of 7.8.

The vulnerability can be exploited by a local attacker with low privileges (PR:L). It requires local access (AV:L) and low attack complexity (AC:L) with no user interaction (UI:N), allowing the attacker to achieve high impacts on confidentiality, integrity, and availability (C:H/I:H/A:H) within the affected system's scope (S:U). Successful exploitation could enable arbitrary code execution or system compromise from a low-privileged context.

Red Hat has addressed the vulnerability through multiple errata releases, including RHSA-2025:2500, RHSA-2025:2502, RHSA-2025:2861, RHSA-2025:2862, and RHSA-2025:2865, which provide updated packages for affected X.Org and Xwayland components in various Red Hat Enterprise Linux versions. Security practitioners should apply these patches promptly to mitigate the risk.

Details

CWE(s)
CWE-119

Affected Products

tigervnc
tigervnc
all versions
x.org
x server
≤ 21.1.16
x.org
xwayland
≤ 24.1.6
redhat
enterprise linux
7.0, 8.0, 9.0

MITRE ATT&CK Enterprise Techniques

T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
Why these techniques?

Buffer overflow and related memory corruption vulnerabilities (e.g., use-after-free, heap overflow) in Xwayland, as used in TigerVNC remote display system, enable remote code execution via exploitation of the remote service.

References