# CVE-2026-55191: freerdp3-shadow-x11: FreeRDP is a free implementation of the Remote Desktop Protocol

CVE-2026-55191 is fixed in 34 products on 1 platform, first by DEBIAN-CVE-2026-55191, released July 8, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-55191
- Priority: High
- CVSS: 9.8 (Medium)
- EPSS: 0.0062
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 8, 2026

## Description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, FreeRDP clients that negotiate RDPGFX AVC444 with an H.264 decoder backend calculate the intermediate YUV444 allocation size in libfreerdp/codec/h264.c with 32-bit multiplication in avc444_ensure_buffer. A malicious RDP server can supply surface dimensions for which piDstStride multiplied by padDstHeight wraps to a small nonzero value, causing winpr_aligned_recalloc to allocate an undersized buffer before YUV420CombineToYUV444 writes using the actual stride and rectangle dimensions. This can cause a client crash and may permit code execution through attacker-influenced heap corruption. This issue is fixed in version 3.27.0.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | freerdp amzn 2023 | 2:3.6.3-1.amzn2023.0.13 | [ALAS2023-2026-2012](https://patchblox.com/security/data/fix/linux/alas2023-2026-2012.md) | Aug 3, 2026 |
| Linux | freerdp-debuginfo amzn 2023 | 2:3.6.3-1.amzn2023.0.13 | [ALAS2023-2026-2012](https://patchblox.com/security/data/fix/linux/alas2023-2026-2012.md) | Aug 3, 2026 |
| Linux | freerdp-debugsource amzn 2023 | 2:3.6.3-1.amzn2023.0.13 | [ALAS2023-2026-2012](https://patchblox.com/security/data/fix/linux/alas2023-2026-2012.md) | Aug 3, 2026 |
| Linux | freerdp-devel amzn 2023 | 2:3.6.3-1.amzn2023.0.13 | [ALAS2023-2026-2012](https://patchblox.com/security/data/fix/linux/alas2023-2026-2012.md) | Aug 3, 2026 |
| Linux | freerdp-libs amzn 2023 | 2:3.6.3-1.amzn2023.0.13 | [ALAS2023-2026-2012](https://patchblox.com/security/data/fix/linux/alas2023-2026-2012.md) | Aug 3, 2026 |
| Linux | freerdp-libs-debuginfo amzn 2023 | 2:3.6.3-1.amzn2023.0.13 | [ALAS2023-2026-2012](https://patchblox.com/security/data/fix/linux/alas2023-2026-2012.md) | Aug 3, 2026 |
| Linux | freerdp-proxy Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [freerdp-proxy 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp-proxy-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | freerdp-proxy-modules Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [freerdp-proxy-modules 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp-proxy-modules-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | freerdp-sdl Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [freerdp-sdl 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp-sdl-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | freerdp-server amzn 2023 | 2:3.6.3-1.amzn2023.0.13 | [ALAS2023-2026-2012](https://patchblox.com/security/data/fix/linux/alas2023-2026-2012.md) | Aug 3, 2026 |
| Linux | freerdp-server-debuginfo amzn 2023 | 2:3.6.3-1.amzn2023.0.13 | [ALAS2023-2026-2012](https://patchblox.com/security/data/fix/linux/alas2023-2026-2012.md) | Aug 3, 2026 |
| Linux | freerdp-shadow-x11 Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [freerdp-shadow-x11 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp-shadow-x11-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | freerdp-wayland Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [freerdp-wayland 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp-wayland-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | freerdp-x11 Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [freerdp-x11 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp-x11-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | freerdp3 Debian 14 | 3.27.0+dfsg-1 | [DEBIAN-CVE-2026-55191](https://patchblox.com/security/data/fix/linux/debian-cve-2026-55191.md) | Jul 8, 2026 |
| Linux | freerdp3-proxy Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [freerdp3-proxy 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp3-proxy-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | freerdp3-proxy-modules Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [freerdp3-proxy-modules 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp3-proxy-modules-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | freerdp3-sdl Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [freerdp3-sdl 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp3-sdl-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | freerdp3-shadow-x11 Ubuntu 24.04.5 LTS (noble) | 3.30.0+dfsg-0ubuntu0.24.04.1 | [freerdp3-shadow-x11 3.30.0+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-freerdp3-shadow-x11-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 |
| Linux | freerdp3-shadow-x11 Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [freerdp3-shadow-x11 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp3-shadow-x11-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | freerdp3-wayland Ubuntu 24.04.5 LTS (noble) | 3.30.0+dfsg-0ubuntu0.24.04.1 | [freerdp3-wayland 3.30.0+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-freerdp3-wayland-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 |
| Linux | freerdp3-wayland Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [freerdp3-wayland 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp3-wayland-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | freerdp3-x11 Ubuntu 24.04.5 LTS (noble) | 3.30.0+dfsg-0ubuntu0.24.04.1 | [freerdp3-x11 3.30.0+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-freerdp3-x11-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 |
| Linux | freerdp3-x11 Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [freerdp3-x11 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-freerdp3-x11-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | libfreerdp-client3-3 Ubuntu 24.04.5 LTS (noble) | 3.30.0+dfsg-0ubuntu0.24.04.1 | [libfreerdp-client3-3 3.30.0+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libfreerdp-client3-3-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 |
| Linux | libfreerdp-client3-3 Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [libfreerdp-client3-3 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libfreerdp-client3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | libfreerdp-server-proxy3-3 Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [libfreerdp-server-proxy3-3 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libfreerdp-server-proxy3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | libfreerdp-server3-3 Ubuntu 24.04.5 LTS (noble) | 3.30.0+dfsg-0ubuntu0.24.04.1 | [libfreerdp-server3-3 3.30.0+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libfreerdp-server3-3-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 |
| Linux | libfreerdp-server3-3 Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [libfreerdp-server3-3 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libfreerdp-server3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | libfreerdp-shadow-subsystem3-3 Ubuntu 24.04.5 LTS (noble) | 3.30.0+dfsg-0ubuntu0.24.04.1 | [libfreerdp-shadow-subsystem3-3 3.30.0+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libfreerdp-shadow-subsystem3-3-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 |
| Linux | libfreerdp-shadow-subsystem3-3 Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [libfreerdp-shadow-subsystem3-3 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libfreerdp-shadow-subsystem3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | libfreerdp-shadow3-3 Ubuntu 24.04.5 LTS (noble) | 3.30.0+dfsg-0ubuntu0.24.04.1 | [libfreerdp-shadow3-3 3.30.0+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libfreerdp-shadow3-3-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 |
| Linux | libfreerdp-shadow3-3 Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [libfreerdp-shadow3-3 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libfreerdp-shadow3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | libfreerdp3-3 Ubuntu 24.04.5 LTS (noble) | 3.30.0+dfsg-0ubuntu0.24.04.1 | [libfreerdp3-3 3.30.0+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libfreerdp3-3-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 |
| Linux | libfreerdp3-3 Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [libfreerdp3-3 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libfreerdp3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | libwinpr amzn 2023 | 2:3.6.3-1.amzn2023.0.13 | [ALAS2023-2026-2012](https://patchblox.com/security/data/fix/linux/alas2023-2026-2012.md) | Aug 3, 2026 |
| Linux | libwinpr-debuginfo amzn 2023 | 2:3.6.3-1.amzn2023.0.13 | [ALAS2023-2026-2012](https://patchblox.com/security/data/fix/linux/alas2023-2026-2012.md) | Aug 3, 2026 |
| Linux | libwinpr-devel amzn 2023 | 2:3.6.3-1.amzn2023.0.13 | [ALAS2023-2026-2012](https://patchblox.com/security/data/fix/linux/alas2023-2026-2012.md) | Aug 3, 2026 |
| Linux | libwinpr-tools3-3 Ubuntu 24.04.5 LTS (noble) | 3.30.0+dfsg-0ubuntu0.24.04.1 | [libwinpr-tools3-3 3.30.0+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libwinpr-tools3-3-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 |
| Linux | libwinpr-tools3-3 Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [libwinpr-tools3-3 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libwinpr-tools3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | libwinpr3-3 Ubuntu 24.04.5 LTS (noble) | 3.30.0+dfsg-0ubuntu0.24.04.1 | [libwinpr3-3 3.30.0+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-libwinpr3-3-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 |
| Linux | libwinpr3-3 Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [libwinpr3-3 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-libwinpr3-3-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | winpr-utils Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [winpr-utils 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-winpr-utils-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |
| Linux | winpr3-utils Ubuntu 24.04.5 LTS (noble) | 3.30.0+dfsg-0ubuntu0.24.04.1 | [winpr3-utils 3.30.0+dfsg-0ubuntu0.24.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-noble-winpr3-utils-3.30.0-dfsg-0ubuntu0.24.04.1.md) | Jul 23, 2026 |
| Linux | winpr3-utils Ubuntu 26.04.1 LTS (resolute) | 3.30.0+dfsg-0ubuntu0.26.04.1 | [winpr3-utils 3.30.0+dfsg-0ubuntu0.26.04.1](https://patchblox.com/security/data/fix/linux/ubuntu-resolute-winpr3-utils-3.30.0-dfsg-0ubuntu0.26.04.1.md) | Nov 7, 2026 |

---

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