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EPSS 0.8%top 43%

Prior to 3.27.0, FreeRDP clients that negotiate RDPGFX AVC444 with an H.264 decoder backend calculate the intermediate YUV444 allocation size in… (CVE-2026-55191)

0
Medium
VulnerabilityCVE-2026-55191gcveosvubuntu-cve-2026-55191ubuntu-16-04-ltsubuntu-pro-18-04-ltsubuntu-18-04-ltsubuntu-pro-20-04-ltsubuntu-22-04-ltsubuntu-24-04-ltsubuntu-pro-24-04-ltsubuntu-25-10ubuntu-26-04-ltscve-2026-55191
Published: 07/09/2026 (07/09/2026, 00:00:00 UTC)
Source: GCVE Database
Product: freerdp

Description

FreeRDP versions prior to 3.27.0 contain a vulnerability in the RDPGFX AVC444 negotiation with an H.264 decoder backend. The issue arises from a 32-bit multiplication overflow when calculating YUV444 buffer allocation size, leading to undersized buffer allocation and potential heap corruption. This can cause client crashes and may allow remote code execution if exploited by a malicious RDP server. The vulnerability is fixed in FreeRDP version 3.27.0.

CVSS v3.1

Score 9.8critical

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected software

Ubuntu:16.04:LTSmore threats →ghsa
freerdp
pkg:deb/ubuntu/freerdp?arch=source&distro=xenial
Affected versions
=1.1.0~git20140921.1.440916e+dfsg1-5ubuntu1=1.1.0~git20140921.1.440916e+dfsg1-5ubuntu1.2=1.1.0~git20140921.1.440916e+dfsg1-5ubuntu1.3=1.1.0~git20140921.1.440916e+dfsg1-5ubuntu1.4
Ubuntu:Pro:18.04:LTSmore threats →ghsa
freerdp2
pkg:deb/ubuntu/freerdp2?arch=source&distro=esm-infra/bionic
Affected versions
=2.0.0~git20170725.1.1648deb+dfsg1-1=2.0.0~git20170725.1.1648deb+dfsg1-5=2.0.0~git20170725.1.1648deb+dfsg1-5ubuntu1=2.0.0~git20170725.1.1648deb+dfsg1-5ubuntu2=2.0.0~git20170725.1.1648deb+dfsg1-6=2.0.0~git20170725.1.1648deb+dfsg1-6build1=2.0.0~git20170725.1.1648deb+dfsg1-7=2.0.0~git20170725.1.1648deb+dfsg1-7ubuntu0.1=2.1.1+dfsg1-0ubuntu0.18.04.1=2.2.0+dfsg1-0ubuntu0.18.04.1=2.2.0+dfsg1-0ubuntu0.18.04.2=2.2.0+dfsg1-0ubuntu0.18.04.3=2.2.0+dfsg1-0ubuntu0.18.04.4=2.2.0+dfsg1-0ubuntu0.18.04.4+esm1=2.2.0+dfsg1-0ubuntu0.18.04.4+esm2=2.2.0+dfsg1-0ubuntu0.18.04.4+esm3=2.2.0+dfsg1-0ubuntu0.18.04.4+esm4=2.2.0+dfsg1-0ubuntu0.18.04.4+esm5=2.2.0+dfsg1-0ubuntu0.18.04.4+esm6
Ubuntu:18.04:LTSmore threats →ghsa
freerdp
pkg:deb/ubuntu/freerdp?arch=source&distro=bionic
Affected versions
=1.1.0~git20140921.1.440916e+dfsg1-15ubuntu1=1.1.0~git20140921.1.440916e+dfsg1-15ubuntu1.18.04.1=1.1.0~git20140921.1.440916e+dfsg1-15ubuntu1.18.04.2
Ubuntu:Pro:20.04:LTSmore threats →ghsa
freerdp2
pkg:deb/ubuntu/freerdp2?arch=source&distro=esm-infra/focal
Affected versions
=2.0.0~git20190204.1.2693389a+dfsg1-1=2.0.0~git20190204.1.2693389a+dfsg1-2=2.0.0~git20190204.1.2693389a+dfsg1-2build1=2.0.0~git20190204.1.2693389a+dfsg1-2build2=2.1.1+dfsg1-0ubuntu0.20.04.1=2.2.0+dfsg1-0ubuntu0.20.04.1=2.2.0+dfsg1-0ubuntu0.20.04.2=2.2.0+dfsg1-0ubuntu0.20.04.3=2.2.0+dfsg1-0ubuntu0.20.04.4=2.2.0+dfsg1-0ubuntu0.20.04.5=2.2.0+dfsg1-0ubuntu0.20.04.6=2.6.1+dfsg1-0ubuntu0.20.04.1=2.6.1+dfsg1-0ubuntu0.20.04.2=2.6.1+dfsg1-0ubuntu0.20.04.2+esm1=2.6.1+dfsg1-0ubuntu0.20.04.2+esm2=2.6.1+dfsg1-0ubuntu0.20.04.2+esm3=2.6.1+dfsg1-0ubuntu0.20.04.2+esm4
Ubuntu:22.04:LTSmore threats →ghsa
freerdp2
pkg:deb/ubuntu/freerdp2?arch=source&distro=jammy
Affected versions
=2.3.0+dfsg1-2build1=2.3.0+dfsg1-2ubuntu1=2.3.0+dfsg1-2ubuntu2=2.4.1+dfsg1-1=2.4.1+dfsg1-1ubuntu1=2.4.1+dfsg1-1ubuntu2=2.5.0+dfsg1-1=2.6.0+dfsg1-1=2.6.1+dfsg1-1=2.6.1+dfsg1-3=2.6.1+dfsg1-3ubuntu1=2.6.1+dfsg1-3ubuntu2=2.6.1+dfsg1-3ubuntu2.1=2.6.1+dfsg1-3ubuntu2.2=2.6.1+dfsg1-3ubuntu2.3=2.6.1+dfsg1-3ubuntu2.4=2.6.1+dfsg1-3ubuntu2.5=2.6.1+dfsg1-3ubuntu2.6=2.6.1+dfsg1-3ubuntu2.7=2.6.1+dfsg1-3ubuntu2.8=2.6.1+dfsg1-3ubuntu2.9=2.6.1+dfsg1-3ubuntu2.10=2.6.1+dfsg1-3ubuntu2.11
Ubuntu:24.04:LTSmore threats →ghsa
freerdp3
pkg:deb/ubuntu/freerdp3?arch=source&distro=noble
Affected versions
<3.30.0+dfsg-0ubuntu0.24.04.1=3.4.0+dfsg1-0ubuntu2=3.4.0+dfsg1-0ubuntu3=3.4.0+dfsg1-0ubuntu4=3.5.0+dfsg1-0ubuntu1=3.5.1+dfsg1-0ubuntu1=3.5.1+dfsg1-0ubuntu1.1=3.5.1+dfsg1-0ubuntu1.2=3.5.1+dfsg1-0ubuntu1.4=3.5.1+dfsg1-0ubuntu1.5=3.5.1+dfsg1-0ubuntu1.6
Ubuntu:Pro:24.04:LTSmore threats →ghsa
freerdp2
pkg:deb/ubuntu/freerdp2?arch=source&distro=esm-apps/noble
Affected versions
=2.10.0+dfsg1-1.1ubuntu1=2.11.2+dfsg1-1=2.11.2+dfsg1-1build1=2.11.2+dfsg1-1build3=2.11.5+dfsg1-1build1=2.11.5+dfsg1-1build2=2.11.5+dfsg1-1ubuntu0.1~esm1=2.11.5+dfsg1-1ubuntu0.1~esm2=2.11.5+dfsg1-1ubuntu0.1~esm3=2.11.5+dfsg1-1ubuntu0.1~esm4=2.11.5+dfsg1-1ubuntu0.1~esm5=2.11.5+dfsg1-1ubuntu0.1~esm6
Ubuntu:25.10more threats →ghsa
freerdp3
pkg:deb/ubuntu/freerdp3?arch=source&distro=questing
Affected versions
=3.14.0+dfsg-1ubuntu1=3.15.0+dfsg-2.1=3.16.0+dfsg-1ubuntu1=3.16.0+dfsg-2=3.16.0+dfsg-2ubuntu0.1=3.16.0+dfsg-2ubuntu0.3=3.16.0+dfsg-2ubuntu0.4=3.16.0+dfsg-2ubuntu0.5
Ubuntu:26.04:LTSmore threats →ghsa
freerdp3
pkg:deb/ubuntu/freerdp3?arch=source&distro=resolute
Affected versions
<3.30.0+dfsg-0ubuntu0.26.04.1=3.16.0+dfsg-2=3.18.0+dfsg-1ubuntu1=3.19.0+dfsg-1=3.19.1+dfsg-1=3.20.0+dfsg-1=3.20.2+dfsg-1=3.21.0+dfsg-1=3.22.0+dfsg-1=3.24.1+dfsg-1ubuntu1=3.24.2+dfsg-1ubuntu1=3.24.2+dfsg-1ubuntu1.1

Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.

AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 09/24/2026, 08:23:15 UTC

Technical Analysis

FreeRDP clients before version 3.27.0 that negotiate RDPGFX AVC444 with an H.264 decoder backend calculate the intermediate YUV444 allocation size using 32-bit multiplication in the avc444_ensure_buffer function. A malicious RDP server can supply surface dimensions causing the multiplication of piDstStride and padDstHeight to overflow and wrap to a small nonzero value. This results in winpr_aligned_recalloc allocating an undersized buffer. Subsequent writes by YUV420CombineToYUV444 using the actual stride and rectangle dimensions can cause heap corruption, potentially leading to client crashes or remote code execution. The issue is addressed in FreeRDP 3.27.0.

Potential Impact

A malicious RDP server can exploit this vulnerability to cause a FreeRDP client crash (denial of service) or potentially execute arbitrary code on the client system through heap corruption. This impacts confidentiality, integrity, and availability of the affected client systems.

Mitigation Recommendations

A fix is available in FreeRDP version 3.27.0. Users and administrators should update to version 3.27.0 or later to remediate this vulnerability. The Ubuntu security advisory USN-8561-1 confirms the availability of patched package versions for supported Ubuntu releases. Standard system updates applying these package versions will mitigate the issue.

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Technical Details

Gcve Source
db.gcve.eu
Osv Id
UBUNTU-CVE-2026-55191
Osv Schema Version
1.7.0
Ecosystems
["Ubuntu:16.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:18.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:Pro:24.04:LTS","Ubuntu:25.10","Ubuntu:26.04:LTS"]

Threat ID: 6a5e7a702a4a8d59899de95b

Added to database: 07/20/2026, 19:43:44 UTC

Last enriched: 09/24/2026, 08:23:15 UTC

Last updated: 10/19/2026, 06:48:18 UTC

Views: 61

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