CVE-2026-55194

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{"affected": [{"affectedData": [{"product": "FreeRDP", "vendor": "FreeRDP", "versions": [{"status": "affected", "version": "< 3.27.0"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*", "matchCriteriaId": "F9603C86-160B-40E9-BA5D-813AA03B1A44", "versionEndExcluding": "3.27.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, rpc_client_recv_fragment in libfreerdp/core/gateway/rpc_client.c ensures the response reassembly stream capacity using only the server-declared alloc_hint rather than the actual StubLength about to be written. A malicious TS Gateway can send a PTYPE_RESPONSE with a small alloc_hint and a much larger frag_length, causing Stream_Write to copy attacker-controlled stub data beyond the 4096-byte pdu->s buffer. This can crash the client and may permit code execution through heap corruption. This issue is fixed in version 3.27.0."}, {"lang": "es", "value": "FreeRDP es una implementaci\u00f3n gratuita del Protocolo de Escritorio Remoto. Antes de la versi\u00f3n 3.27.0, rpc_client_recv_fragment en libfreerdp/core/gateway/rpc_client.c asegura la capacidad del flujo de reensamblaje de la respuesta utilizando solo el alloc_hint declarado por el servidor en lugar del StubLength real que est\u00e1 a punto de escribirse. Una puerta de enlace TS maliciosa puede enviar un PTYPE_RESPONSE con un alloc_hint peque\u00f1o y un frag_length mucho mayor, haciendo que Stream_Write copie datos stub controlados por el atacante m\u00e1s all\u00e1 del b\u00fafer pdu -> s de 4096 bytes. Esto puede bloquear al cliente y puede permitir la ejecuci\u00f3n de c\u00f3digo a trav\u00e9s de la corrupci\u00f3n de la pila. Este problema se solucion\u00f3 en la versi\u00f3n 3.27.0."}], "id": "CVE-2026-55194", "lastModified": "2026-10-26T11:10:00.157", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "nvd@nist.gov", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.7, "baseSeverity": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "PASSIVE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-55194", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-08-21T03:55:49.884406Z", "version": "2.0.3"}}]}, "published": "2026-08-19T18:16:44.857", "references": [{"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/FreeRDP/FreeRDP/commit/9f2da52c2341cc14a96ad12e69c5b83d0bcd8b5a"}, {"source": "security-advisories@github.com", "tags": ["Issue Tracking", "Patch"], "url": "https://github.com/FreeRDP/FreeRDP/pull/12873"}, {"source": "security-advisories@github.com", "tags": ["Release Notes"], "url": "https://github.com/FreeRDP/FreeRDP/releases/tag/3.27.0"}, {"source": "security-advisories@github.com", "tags": ["Exploit", "Mitigation", "Vendor Advisory"], "url": "https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-9gxm-3mf5-f5cx"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-122"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{"bugzilla": {"description": "FreeRDP: FreeRDP: Heap-buffer-overflow allows arbitrary code execution via crafted RPC response", "id": "2519824", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2519824"}, "csaw": false, "cvss3": {"cvss3_base_score": "8.8", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-120", "details": ["FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, rpc_client_recv_fragment in libfreerdp/core/gateway/rpc_client.c ensures the response reassembly stream capacity using only the server-declared alloc_hint rather than the actual StubLength about to be written. A malicious TS Gateway can send a PTYPE_RESPONSE with a small alloc_hint and a much larger frag_length, causing Stream_Write to copy attacker-controlled stub data beyond the 4096-byte pdu->s buffer. This can crash the client and may permit code execution through heap corruption. This issue is fixed in version 3.27.0.", "A flaw was found in FreeRDP. A remote attacker, specifically a malicious TS Gateway, can exploit a heap-buffer-overflow vulnerability by sending a specially crafted Remote Desktop Protocol (RDP) response. This occurs because the client incorrectly uses a smaller `alloc_hint` value instead of the actual `StubLength` for buffer capacity during response reassembly. This allows attacker-controlled data to be written beyond the intended buffer, leading to a client crash and potentially enabling arbitrary code execution."], "mitigation": {"lang": "en:us", "value": "To mitigate this vulnerability, avoid connecting through untrusted TS Gateways (RD Gateways) or disable gateway parameters (such as omitting `/g:` in `xfreerdp`) to force direct RDP connections and bypass RPC response parsing."}, "name": "CVE-2026-55194", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "freerdp", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "freerdp", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "freerdp", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "freerdp", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "freerdp", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-08-19T17:50:30Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-55194\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-55194\nhttps://github.com/FreeRDP/FreeRDP/commit/9f2da52c2341cc14a96ad12e69c5b83d0bcd8b5a\nhttps://github.com/FreeRDP/FreeRDP/pull/12873\nhttps://github.com/FreeRDP/FreeRDP/releases/tag/3.27.0\nhttps://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-9gxm-3mf5-f5cx"], "statement": "A heap buffer overflow flaw was found in FreeRDP's TS Gateway RPC client (`libfreerdp/core/gateway/rpc_client.c`). During response fragment reassembly in `rpc_client_recv_fragment`, stream allocation relies on the server-provided `alloc_hint` rather than the actual `StubLength`. A malicious TS Gateway can send a `PTYPE_RESPONSE` packet with a small `alloc_hint` and a larger payload, causing `Stream_Write` to overwrite memory beyond the fixed 4096-byte buffer (`pdu->s`). This can result in client crashes or potential arbitrary code execution.", "threat_severity": "Important"}

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