X.Org Xwayland Buffer Overflow via XkbVModMaskText
CVE-2025-26595 Published on February 25, 2025

Xorg: xwayland: buffer overflow in xkbvmodmasktext()
A buffer overflow flaw was found in X.Org and Xwayland. The code in XkbVModMaskText() allocates a fixed-sized buffer on the stack and copies the names of the virtual modifiers to that buffer. The code fails to check the bounds of the buffer and would copy the data regardless of the size.

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Vulnerability Analysis

CVE-2025-26595 can be exploited 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 be very high.

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

Timeline

Reported to Red Hat.

Made public. 13 days later.

Weakness Type

What is a Stack Overflow Vulnerability?

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).

CVE-2025-26595 has been classified to as a Stack Overflow vulnerability or weakness.


Products Associated with CVE-2025-26595

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2025-26595 are published in these products:

Tigervnc
 
Xorg X Server
 
Xorg Xwayland
 
Red Hat Enterprise Linux (RHEL)
 
Red Hat Rhel Els
 
Red Hat Rhel Aus
 
Red Hat Rhel E4s
 
Red Hat Rhel Tus
 
Red Hat Rhel Eus
 

Exploit Probability

EPSS
0.06%
Percentile
18.02%

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.