{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-66402", "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "state": "PUBLISHED", "assignerShortName": "VulnCheck", "dateReserved": "2026-07-26T12:22:34.139Z", "datePublished": "2026-08-01T12:22:17.331Z", "dateUpdated": "2026-08-01T12:22:17.331Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10", "shortName": "VulnCheck", "dateUpdated": "2026-08-01T12:22:17.331Z"}, "datePublic": "2026-07-15T00:00:00.000Z", "title": "FreeRDP before 3.29.0 TLS Certificate Identity Validation Bypass", "descriptions": [{"lang": "en", "value": "FreeRDP before 3.29.0 (affected versions <= 3.28.0) contains multiple TLS certificate identity validation weaknesses in tls_verify_certificate(), tls_match_hostname(), and x509_utils_get_dns_names(). Because FreeRDP performs custom Common Name and DNS SAN string matching instead of using OpenSSL's length-aware identity validation APIs, it (1) truncates DNS SAN values at embedded NUL bytes (accepting e.g. 'victim.example\\0.attacker.example' as 'victim.example'), (2) accepts a matching Common Name even when non-matching DNS SAN entries are present, and (3) accepts IP-literal targets via DNS/CN matching without comparing iPAddress SANs. Under a trusted or misissued certificate chain, an attacker positioned to present such a certificate can bypass server identity verification, weakening TLS server authentication."}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "Improper Certificate Validation", "cweId": "CWE-295", "type": "CWE"}]}], "affected": [{"vendor": "FreeRDP", "product": "FreeRDP", "defaultStatus": "unaffected", "versions": [{"version": "0", "status": "affected", "versionType": "semver", "lessThan": "3.29.0"}, {"version": "3.29.0", "status": "unaffected", "versionType": "semver"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*", "versionEndExcluding": "3.29.0"}]}]}], "metrics": [{"cvssV4_0": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "baseScore": 9.3, "baseSeverity": "CRITICAL", "exploitMaturity": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "format": "CVSS"}, {"cvssV3_1": {"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"}, "format": "CVSS"}], "references": [{"url": "https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-43hh-p3vw-hfx3", "tags": ["vendor-advisory"], "name": "GitHub Security Advisory (GHSA-43hh-p3vw-hfx3)"}, {"url": "https://github.com/FreeRDP/FreeRDP/commit/b9533f07f98c25ed01c5f543b4d0ce73e120f5fd", "tags": ["patch"], "name": "Patch Commit"}, {"name": "VulnCheck Advisory: FreeRDP before 3.29.0 TLS Certificate Identity Validation Bypass", "tags": ["third-party-advisory"], "url": "https://www.vulncheck.com/advisories/freerdp-before-tls-certificate-identity-validation-bypass"}], "credits": [{"lang": "en", "value": "1121984919", "type": "reporter"}], "x_generator": {"engine": "vulncheck-endgame"}}}}

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{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,3.29.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "3.29.0"}}], "enrichment": {"confidence": 95.0, "confidence_source": "inferred", "scores": [{"score": 95.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "FreeRDP", "source": "cna", "vendor": "FreeRDP"}, "product": "freerdp", "vendor": "freerdp"}], "created": "2026-08-01T14:00:06.025001+00:00", "updated": "2026-08-01T14:00:06.025021+00:00", "vendors": ["freerdp", "freerdp$PRODUCT$freerdp"]}