CVE-2026-55191: FreeRDP is a free implementation of the Remote Desktop Protocol

Q: How do I fix CVE-2026-55191?

freerdp: upgrade to 3.27.0. Exact commands for each OS are on this page.

Q: Is CVE-2026-55191 being exploited?

CVE-2026-55191 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-55191 affect?

CVE-2026-55191 affects freerdp. Severity is critical (CVSS 9.8). 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 3

Q: How urgent is CVE-2026-55191?

Priority 57/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2026-55191 is a critical-severity flaw (CVSS 9.8) affecting freerdp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 51%)
CISA exploited list	No
Weakness	CWE-122, CWE-190
Published	2026-08-19
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: freerdp

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-19 18:16 UTCPublished CVE record published
2026-10-26 11:10 UTCUpdated Record last modified

freerdp freerdp UPGRADE

Affected: < 3.27.0

Fixed in: 3.27.0

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy freerdp || rpm -q freerdp || freerdp --version

2. UPGRADE to 3.27.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade freerdp

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade freerdp

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Exact fixes by distribution

Fedora 46 · flare-im · FIXED · 0.22.7-1.fc46 · FEDORA-2026-cd5e8062a1 · source

sudo dnf upgrade --advisory=FEDORA-2026-cd5e8062a1

Fedora ELN · libdnf · FIXED · 0.76.0-2.eln159 · FEDORA-2026-dbd263e9d4 · source

sudo dnf upgrade --advisory=FEDORA-2026-dbd263e9d4

Debian 12 · freerdp2 · NO FIX YET

Debian 13 · freerdp3 · NO FIX YET

RHEL 10 · freerdp · NOT AFFECTED

RHEL 6 · freerdp · DEFERRED

RHEL 7 · freerdp · NOT AFFECTED

RHEL 8 · freerdp · NOT AFFECTED

RHEL 9 · freerdp · NOT AFFECTED

Alpine 3.24 · freerdp · FIXED · freerdp-3.27.1-r0

apk add --upgrade freerdp apk info -v freerdp

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-2012 · source

sudo dnf update --advisory=ALAS2023-2026-2012

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-55191?

freerdp: upgrade to 3.27.0. Exact commands for each OS are on this page.

Is CVE-2026-55191 being exploited?

CVE-2026-55191 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-55191 affect?

CVE-2026-55191 affects freerdp. Severity is critical (CVSS 9.8). 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 3

How urgent is CVE-2026-55191?

Priority 57/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

WinRM and RDP vulnerabilities

Related CVEs

CVE-2026-109940 MEDIUM 4.3 UPGRADE FreeRDP 3.0.0-beta1 before 3.32.0 on Unix builds with PKCS#11 support has a stack-based buffer overflow in wpr
CVE-2026-109939 MEDIUM 6.5 UPGRADE FreeRDP 3.27.1 before 3.32.0 contains a NULL pointer dereference in update_read_cache_bitmap_v3_order() in lib
CVE-2026-109938 MEDIUM 6.5 UPGRADE Positive mapped-video coordinates overflow and abort FreeRDP clients A malicious or compromised RDP server can
CVE-2026-109941 MEDIUM 6.5 UPGRADE FreeRDP from 2.3.0 before 3.32.0 contains an infinite loop vulnerability in http_chuncked_read that allows mal
CVE-2026-109942 MEDIUM 6.5 UPGRADE FreeRDP 2.3.0 before 3.32.0 dereferences a NULL stream in rdg_process_close_packet in libfreerdp/core/gateway/

References

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