CVE-2023-3138

libX11: InitExt.c can overwrite unintended portions of the Display structure if the extension request leads to a buffer overflow

Published Jun 28, 2023 CVSS 3.1 · 7.5 High EPSS 1.7% KEV · Not listed
Description
A vulnerability was found in libX11. The security flaw occurs because the functions in src/InitExt.c in libX11 do not check that the values provided for the Request, Event, or Error IDs are within the bounds of the arrays that those functions write to, using those IDs as array indexes. They trust that they were called with values provided by an Xserver adhering to the bounds specified in the X11 protocol, as all X servers provided by X.Org do. As the protocol only specifies a single byte for these values, an out-of-bounds value provided by a malicious server (or a malicious proxy-in-the-middle) can only overwrite other portions of the Display structure and not write outside the bounds of the Display structure itself, possibly causing the client to crash with this memory corruption.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-3472-1 libx11 security update
Debian DSA Debian DSA DSA-5433-1 libx11 security update
EUVD EUVD EUVD-2023-43823 A vulnerability was found in libX11. The security flaw occurs because the functions in src/InitExt.c in libX11 do not check that the values provided for the Request, Event, or Error IDs are within the bounds of the arrays that those functions write to, using those IDs as array indexes. They trust that they were called with values provided by an Xserver adhering to the bounds specified in the X11 protocol, as all X servers provided by X.Org do. As the protocol only specifies a single byte for these values, an out-of-bounds value provided by a malicious server (or a malicious proxy-in-the-middle) can only overwrite other portions of the Display structure and not write outside the bounds of the Display structure itself, possibly causing the client to crash with this memory corruption.
Ubuntu USN Ubuntu USN USN-6168-1 libx11 vulnerability
Ubuntu USN Ubuntu USN USN-6168-2 libx11 vulnerability
History

No history.

Weaknesses

Sources

Status
PUBLISHED
Assigner
redhat
Published
Updated
Aug 2, 2024, 6:48 AM
Reserved
Jun 7, 2023, 12:00 AM
Status
Modified
Published
Jun 28, 2023, 9:15 PM
Modified
Jun 17, 2026, 6:13 AM
Severity
Moderate
Public date
Jun 15, 2023, 12:00 AM