CVE-2026-44421

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.26.0, a malicious RDP server can trigger a heap-buffer-overflow write in the FreeRDP client by sending crafted RDPGFX PDUs. The bug is in gdi_CacheToSurface: it validates a destination rectangle that is clamped to UINT16_MAX, but then performs the copy using the original cacheEntry->width/height. This can cause a large out-of-bounds heap write and may lead to client crashes or code execution. This bug is reachable from a malicious RDP server, but only when the client has RDPGFX enabled. This vulnerability is fixed in 3.26.0.

CVSS v3 8.8 HIGH

8.8^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.8 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m6ff	Exploit Mitigation Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:36203
https://access.redhat.com/errata/RHSA-2026:46393
https://access.redhat.com/security/cve/CVE-2026-44421
https://bugzilla.redhat.com/show_bug.cgi?id=2483471
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m6ff	Exploit Mitigation Vendor Advisory
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44421.json

Configurations

Configuration 1 (hide)

cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-05-29 20:16

Updated : 2026-07-27 13:18

NVD link : CVE-2026-44421

Mitre link : CVE-2026-44421

CVE.ORG link : CVE-2026-44421

JSON object : View

Products Affected

freerdp

freerdp

CWE

CWE-122

Heap-based Buffer Overflow

CWE-787

Out-of-bounds Write

{"id": "CVE-2026-44421", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-44421", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "total"}], "version": "2.0.3", "timestamp": "2026-06-01T00:00:00+00:00"}}], "cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 8.8, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 2.8}, {"type": "Secondary", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 8.8, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "REQUIRED", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 2.8}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "FreeRDP", "product": "FreeRDP", "versions": [{"status": "affected", "version": "< 3.26.0"}]}]}, {"source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "affectedData": [{"cpes": ["cpe:/o:redhat:enterprise_linux:10.2"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "versions": [{"status": "unaffected", "version": "2:3.10.3-12.el10_2.6", "lessThan": "*", "versionType": "rpm"}], "packageName": "freerdp", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "affected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:6"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 6", "packageName": "freerdp", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unknown"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:7"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 7", "packageName": "freerdp", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:8"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 8", "packageName": "freerdp", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}, {"cpes": ["cpe:/o:redhat:enterprise_linux:9"], "vendor": "Red Hat", "product": "Red Hat Enterprise Linux 9", "packageName": "freerdp", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "defaultStatus": "unaffected"}]}], "published": "2026-05-29T20:16:24.513", "references": [{"url": "https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m6ff", "tags": ["Exploit", "Mitigation", "Vendor Advisory"], "source": "security-advisories@github.com"}, {"url": "https://access.redhat.com/errata/RHSA-2026:36203", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://access.redhat.com/errata/RHSA-2026:46393", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://access.redhat.com/security/cve/CVE-2026-44421", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2483471", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}, {"url": "https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m6ff", "tags": ["Exploit", "Mitigation", "Vendor Advisory"], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}, {"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44421.json", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-122"}]}, {"type": "Secondary", "source": "0b0ca135-0b70-47e7-9f44-1890c2a1c46c", "description": [{"lang": "en", "value": "CWE-787"}]}], "descriptions": [{"lang": "en", "value": "FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.26.0, a malicious RDP server can trigger a heap-buffer-overflow write in the FreeRDP client by sending crafted RDPGFX PDUs. The bug is in gdi_CacheToSurface: it validates a destination rectangle that is clamped to UINT16_MAX, but then performs the copy using the original cacheEntry->width/height. This can cause a large out-of-bounds heap write and may lead to client crashes or code execution. This bug is reachable from a malicious RDP server, but only when the client has RDPGFX enabled. This vulnerability is fixed in 3.26.0."}, {"lang": "es", "value": "FreeRDP es una implementaci\u00f3n gratuita del Protocolo de Escritorio Remoto. Antes de la versi\u00f3n 3.26.0, un servidor RDP malicioso puede desencadenar una escritura de desbordamiento de b\u00fafer de pila en el cliente FreeRDP enviando PDUs RDPGFX manipuladas. El error est\u00e1 en gdi_CacheToSurface: valida un rect\u00e1ngulo de destino que est\u00e1 limitado a UINT16_MAX, pero luego realiza la copia utilizando el ancho/alto original de cacheEntry. Esto puede causar una escritura de pila fuera de l\u00edmites grande y puede llevar a ca\u00eddas del cliente o ejecuci\u00f3n de c\u00f3digo. Este error es alcanzable desde un servidor RDP malicioso, pero solo cuando el cliente tiene RDPGFX habilitado. Esta vulnerabilidad est\u00e1 corregida en la versi\u00f3n 3.26.0."}], "lastModified": "2026-07-27T13:18:07.127", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "186FAA8A-CF9D-40F3-8509-DAC168BFDA2F", "versionEndExcluding": "3.26.0"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}