CVE-2026-55192 FreeRDP: Out-of-bounds read in H.264 YUV-to-RGB conversion due to decoder/surface dimension mismatch

High 7.2 Published 19 Aug 2026 Updated 25 Aug 2026

A malicious RDP server can trigger an out-of-bounds read in FreeRDP's H.264 decoder, potentially disclosing client memory or causing a crash.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: Available

What is CVE-2026-55192?

CVE-2026-55192 is a high-severity vulnerability in Freerdp Freerdp, published on 19 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, FreeRDP H.264 decoder backends can return YUV planes sized from the bitstream without comparing the decoded width and height to the RDPGFX surface dimensions used to validate region rectangles. A malicious RDP server can provide an AVC420 or AVC444 bitstream whose decoded frame is smaller than the negotiated surface, causing yuv420_context_decode and the YUV-to-RGB conversion paths to read beyond the decoder-owned planes in libfreerdp/codec/h264.c and the selected H.264 backend. This can disclose client memory or crash the client. This issue is fixed in version 3.27.0.

Weakness: CWE-125

Which versions are affected by CVE-2026-55192?

It affects 1 product.

Products include Freerdp Freerdp.

How do I fix CVE-2026-55192?

Upgrade to a fixed version.

Is CVE-2026-55192 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55192 exists.

All Freerdp Freerdp vulnerabilities

Sources

Also known as DEBIAN-CVE-2026-55192, GHSA-3mmf-qh4f-frm6, UBUNTU-CVE-2026-55192.