{"id":"CVE-2026-55191","title":"FreeRDP is a free implementation of the Remote Desktop Protocol","summary":"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 wit…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-122","CWE-190","CWE-787"],"vendor":"freerdp","product":"freerdp","affected":["freerdp < 3.27.0"],"patched":["freerdp 3.27.0"],"published":"2026-08-19","updated":"2026-09-22","sourceUpdated":"2026-09-22T19:47:02.713","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-55191","references":[{"url":"https://github.com/FreeRDP/FreeRDP/commit/97f40b9e766af375f4e41ac6a3f4397d708d249c","label":"security-advisories@github.com"},{"url":"https://github.com/FreeRDP/FreeRDP/pull/12873","label":"security-advisories@github.com"},{"url":"https://github.com/FreeRDP/FreeRDP/releases/tag/3.27.0","label":"security-advisories@github.com"},{"url":"https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-vx73-w5q6-7jqr","label":"security-advisories@github.com"},{"url":"https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-vx73-w5q6-7jqr","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-55191.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-55191"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2519817"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-55191"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55191"}],"tags":["nvd","csaf","vex","red-hat"],"epss":0.00598,"epssPercentile":0.47333,"ingestedAt":"2026-09-09T21:22:45.541Z","scores":{"nvd":9.8,"vendor":8.8},"slug":"CVE-2026-55191","body":"## Overview\n\nFreeRDP 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.\n\n## Affected\n\n- `freerdp < 3.27.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `freerdp 3.27.0`\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, … · updated 2026-09-22 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-55191.json)","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":209351,"id":"CVE-2026-55191","ts":1790107850123,"field":"cvss","old":null,"new":"9.8"},{"seq":209350,"id":"CVE-2026-55191","ts":1790107850123,"field":"severity","old":"none","new":"critical"}]}