A flaw was found in the X.Org X server. This vulnerability, an out-of-bounds read, affects the...

Description

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.

Basic information

Type
unreviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Source code
Not specified
Published (advisory)
2026-05-05 18:33:24 UTC
Updated
2026-06-08 06:30:26 UTC
NVD published
2026-05-05 16:16:11 UTC

EPSS Score

Score Percentile
0.03% 8.14%

CVSS Scores

Base score Version Severity Vector
6.1 3.1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:L Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.

Identifiers

CWEs

CWE id Name
CWE-805 Buffer Access with Incorrect Length Value

References

cvelogic Threat Intelligence