CVE-2026-109946
Received Received - Intake

FreeRDP Client AVC444 Region Width Validation Flaw

Publication date: 2026-10-13

Last updated on: 2026-10-13

Assigner: VulnCheck

Description
FreeRDP 3.11.0 before 3.32.0 does not validate that AVC444 and AVC444v2 region widths are even before YUV444 conversion, so an odd width reaches an assertion and aborts the client. A malicious or compromised RDP server can terminate a connected FreeRDP client after RDPGFX AVC444 negotiation by sending an in-bounds region rectangle with an odd width.

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Meta Information

Published
2026-10-13
Last Modified
2026-10-13
Generated
2026-10-13
AI Q&A
2026-10-13
EPSS Evaluated
N/A
NVD
CVE-2026-109946
EUVD
EUVD-2026-98711

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
FreeRDP FreeRDP 3.11.0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-617 The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.

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Executive Summary

CVE-2026-109946 is a vulnerability in FreeRDP where a malicious RDP server can crash the client by sending a region rectangle with an odd width during AVC444 or AVC444v2 negotiation. The client fails to validate the width parity before YUV444 conversion, causing an assertion failure and client termination.

Detection Guidance

To detect this vulnerability, check the FreeRDP version on your system using 'xfreerdp --version' or 'apt list --installed | grep freerdp'. If the version is between 2.0.0 and 3.31.1, the system is vulnerable. Monitor network traffic for RDP sessions using tools like Wireshark to inspect AVC444 negotiation packets for odd-width region rectangles.

Impact Analysis

This vulnerability allows a remote attacker to terminate your FreeRDP client by sending a crafted region rectangle during an active RDP session. The attack requires network access and user interaction to initiate the session but no local privileges. The impact is limited to denial of service, as the client crashes without further compromise.

Mitigation Strategies

Upgrade FreeRDP to version 3.32.0 or later immediately. If upgrading is not possible, disable AVC444 support in FreeRDP by setting the 'disable-encodings' option to exclude AVC444 in client configurations. Ensure RDP servers are trusted to prevent malicious region rectangles.

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