{"id":"CVE-2026-66402","aliases":["CLSA-2026-1791553435","CLSA-2026-1791557610","DEBIAN-CVE-2026-66402","EUVD-2026-51851","GHSA-43hh-p3vw-hfx3","GHSA-759r-h698-g7xj","UBUNTU-CVE-2026-66402"],"status":"published","title":"FreeRDP before 3.29.0 TLS Certificate Identity Validation Bypass","description":"FreeRDP before 3.29.0 (affected versions \u003c= 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.","severity":{"version":"4.0","score":9.3,"vector":"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","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.0034,"percentile":0.27636,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-295"],"published":"2026-08-01T12:22:17Z","modified":"2026-10-28T02:30:45Z","fixes":[{"ecosystem":"Debian:14","package":"freerdp3","fixed_in":["3.29.0+dfsg-1"],"sources":["osv"]},{"ecosystem":"Ubuntu:24.04:LTS","package":"freerdp3","fixed_in":["3.30.0+dfsg-0ubuntu0.24.04.1"],"sources":["osv"]},{"ecosystem":"Ubuntu:26.04:LTS","package":"freerdp3","fixed_in":["3.30.0+dfsg-0ubuntu0.26.04.1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"TuxCare:OracleLinux:7","package":"freerdp","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.1-5.0.9.el7_9.tuxcare.els4"}]}],"bundled":4},{"source":"osv","ecosystem":"TuxCare:OracleLinux:7","package":"freerdp-devel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.1-5.0.9.el7_9.tuxcare.els4"}]}],"bundled":4},{"source":"osv","ecosystem":"TuxCare:OracleLinux:7","package":"freerdp-libs","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.1-5.0.9.el7_9.tuxcare.els4"}]}],"bundled":4},{"source":"osv","ecosystem":"TuxCare:OracleLinux:7","package":"libwinpr","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.1-5.0.9.el7_9.tuxcare.els4"}]}],"bundled":4},{"source":"osv","ecosystem":"TuxCare:OracleLinux:7","package":"libwinpr-devel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.1-5.0.9.el7_9.tuxcare.els4"}]}],"bundled":4},{"source":"osv","ecosystem":"TuxCare:CentOS:7","package":"freerdp","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.1-5.0.9.el7_9.tuxcare.els4"}]}],"bundled":4},{"source":"osv","ecosystem":"TuxCare:CentOS:7","package":"freerdp-devel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.1-5.0.9.el7_9.tuxcare.els4"}]}],"bundled":4},{"source":"osv","ecosystem":"TuxCare:CentOS:7","package":"freerdp-libs","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.1-5.0.9.el7_9.tuxcare.els4"}]}],"bundled":4},{"source":"osv","ecosystem":"TuxCare:CentOS:7","package":"libwinpr","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.1-5.0.9.el7_9.tuxcare.els4"}]}],"bundled":4},{"source":"osv","ecosystem":"TuxCare:CentOS:7","package":"libwinpr-devel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.1-5.0.9.el7_9.tuxcare.els4"}]}],"bundled":4},{"source":"osv","ecosystem":"Debian:12","package":"freerdp2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.10.0+dfsg1-1","2.10.0+dfsg1-1.1","2.11.2+dfsg1-1","2.11.2+dfsg1-1.1~exp1","2.11.2+dfsg1-1.1~exp2","2.11.5+dfsg1-1","2.11.7+dfsg1-1","2.11.7+dfsg1-2","2.11.7+dfsg1-3","2.11.7+dfsg1-4","2.11.7+dfsg1-5","2.11.7+dfsg1-6","2.11.7+dfsg1-6~deb12u1"]},{"source":"osv","ecosystem":"Debian:13","package":"freerdp3","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.15.0+dfsg-2.1","3.15.0+dfsg-2.1+deb13u1","3.15.0+dfsg-2.1+deb13u2","3.15.0+dfsg-2.1+deb13u3","3.16.0+dfsg-1","3.16.0+dfsg-2","3.17.0+dfsg-1","3.17.1+dfsg-1","3.17.1+dfsg-2","3.17.2+dfsg-1","3.17.2+dfsg-2","3.17.2+dfsg-3","3.18.0+dfsg-1","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","3.22.0+dfsg-1~bpo13+0","3.22.0+dfsg-1~bpo13+1","3.22.0+dfsg-3","3.23.0+dfsg-1","3.23.0+dfsg-1~bpo13+1","3.24.0+dfsg-1","3.24.0+dfsg-2","3.24.1+dfsg-1","3.24.2+dfsg-1","3.24.2+dfsg-1~bpo13+1","3.25.0+dfsg-1","3.25.0+dfsg-2","3.25.0+dfsg-3","3.25.0+dfsg-4","3.25.0+dfsg-5","3.26.0+dfsg-1","3.26.0+dfsg-1~bpo13+1","3.27.0+dfsg-1","3.27.1+dfsg-1","3.28.0+dfsg-1","3.28.0+dfsg-2","3.29.0+dfsg-1","3.30.0+dfsg-1","3.30.0+dfsg-1~bpo13+1","3.31.0+dfsg-1","3.31.1+dfsg-1","3.31.1+dfsg-1~bpo13+1","3.32.0+dfsg-1","3.32.1+dfsg-1","3.32.1+dfsg-1~bpo13+1"]},{"source":"osv","ecosystem":"Debian:14","package":"freerdp3","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.29.0+dfsg-1"}]}],"versions":["3.15.0+dfsg-2.1","3.16.0+dfsg-1","3.16.0+dfsg-2","3.17.0+dfsg-1","3.17.1+dfsg-1","3.17.1+dfsg-2","3.17.2+dfsg-1","3.17.2+dfsg-2","3.17.2+dfsg-3","3.18.0+dfsg-1","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","3.22.0+dfsg-1~bpo13+0","3.22.0+dfsg-1~bpo13+1","3.22.0+dfsg-3","3.23.0+dfsg-1","3.23.0+dfsg-1~bpo13+1","3.24.0+dfsg-1","3.24.0+dfsg-2","3.24.1+dfsg-1","3.24.2+dfsg-1","3.24.2+dfsg-1~bpo13+1","3.25.0+dfsg-1","3.25.0+dfsg-2","3.25.0+dfsg-3","3.25.0+dfsg-4","3.25.0+dfsg-5","3.26.0+dfsg-1","3.26.0+dfsg-1~bpo13+1","3.27.0+dfsg-1","3.27.1+dfsg-1","3.28.0+dfsg-1","3.28.0+dfsg-2"]},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"freerdp","ranges":[{"type":"ECOSYSTE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Advisory","Exploit","Mitigation","advisory","report"]},{"url":"https://github.com/FreeRDP/FreeRDP/commit/b9533f07f98c25ed01c5f543b4d0ce73e120f5fd","tags":["patch","Patch","fix","report"]},{"url":"https://www.vulncheck.com/advisories/freerdp-before-tls-certificate-identity-validation-bypass","tags":["third-party-advisory","Patch","Third Party Advisory","advisory","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-66402","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-759r-h698-g7xj"},{"url":"https://errata.tuxcare.com/els_os/oraclelinux7els/CLSA-2026-1791553435.html","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-67289","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-67300","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68580","tags":["advisory"]},{"url":"https://errata.tuxcare.com/els_os/centos7els/CLSA-2026-1791557610.html","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66402.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-66402","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-66402","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-66402","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-66402","title":"FreeRDP before 3.29.0 TLS Certificate Identity Validation Bypass","description":"FreeRDP before 3.29.0 (affected versions \u003c= 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.","status":"published","published":"2026-08-01T12:22:17.331Z","modified":"2026-08-05T03:56:18.042Z","cvss":[{"version":"4.0","score":9.3,"vector":"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","level":"critical","assessor":"cna"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"cna"}],"cwes":["CWE-295"],"updated_at":"2026-11-02T14:20:12.939084Z"}],"euvd":[{"id":"EUVD-2026-51851","description":"FreeRDP before 3.29.0 (affected versions \u003c= 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.","status":"published","published":"2026-08-01T12:22:17Z","modified":"2026-08-05T03:56:18Z","cvss":[{"version":"4.0","score":9.3,"vector":"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","level":"critical"}],"updated_at":"2026-11-02T18:02:22.516769Z"}],"ghsa":[{"id":"GHSA-759r-h698-g7xj","title":"FreeRDP before 3.29.0 (affected versions \u003c= 3.28.0) contains multiple TLS certificate identity...","description":"FreeRDP before 3.29.0 (affected versions \u003c= 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.","status":"published","published":"2026-08-01T15:30:25Z","modified":"2026-08-01T15:30:25Z","cvss":[{"version":"4.0","score":9.3,"vector":"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/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","level":"critical"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-295"],"updated_at":"2026-11-02T15:10:01.548476Z"}],"nvd":[{"id":"CVE-2026-66402","description":"FreeRDP before 3.29.0 (affected versions \u003c= 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.","status":"published","published":"2026-08-01T13:16:57.487Z","modified":"2026-10-02T19:08:13.673Z","cvss":[{"version":"4.0","score":9.3,"vector":"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/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","level":"critical","assessor":"secondary"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"secondary"}],"cwes":["CWE-295"],"updated_at":"2026-11-02T14:12:34.290716Z"}],"osv":[{"id":"CVE-2026-66402","title":"FreeRDP before 3.29.0 TLS Certificate Identity Validation Bypass","description":"FreeRDP before 3.29.0 (affected versions \u003c= 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.","status":"published","published":"2026-08-01T12:22:17.331Z","modified":"2026-10-28T02:30:45.832079255Z","cvss":[{"version":"4.0","score":9.3,"vector":"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","level":"critical"}],"cwes":["CWE-295"],"updated_at":"2026-11-02T15:45:14.46177Z"},{"id":"DEBIAN-CVE-2026-66402","description":"FreeRDP before 3.29.0 (affected versions \u003c= 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.","status":"published","published":"2026-08-01T13:16:57.487Z","modified":"2026-10-03T08:47:31.270112977Z","cvss":[{"version":"4.0","score":9.3,"vector":"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/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","level":"critical"}],"updated_at":"2026-11-02T15:45:58.699079Z"},{"id":"UBUNTU-CVE-2026-66402","description":"FreeRDP before 3.29.0 (affected versions \u003c= 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.","status":"published","published":"2026-08-01T13:16:00Z","modified":"2026-08-17T23:45:11.536798383Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"},{"version":"4.0","score":9.3,"vector":"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","level":"critical"}],"updated_at":"2026-11-02T16:56:53.710209Z"},{"id":"CLSA-2026-1791553435","title":"freerdp: Fix of 4 CVEs","description":"- CVE-2026-68580: reject a FramesPerPacket of INT32_MAX or more in audin_process_open() before it is stored, so a malicious server cannot overflow the per-packet size arithmetic in the audio input backends\n- CVE-2026-66402: return the real length of certificate ASN.1 strings and reject values that are not a host name or IP, so a certificate carrying an embedded NUL can no longer pass identity validation as a shorter, different name\n- CVE-2026-67300: deep-clone WINDOW_STATE_ORDER and NOTIFY_ICON_STATE_ORDER before posting them to the async update queue, and free the clone in the message destructor; the shallow copies referenced parser-owned heap released as soon as the callback returned\n- CVE-2026-67289: validate the server-supplied redirection fields - addresses must parse as IPv4/IPv6, FQDN and NetBIOS name must look like a host, username and domain must not contain line breaks - so CRLF in TargetNetAddress can no longer be injected into the HTTP proxy CONNECT request","status":"published","published":"2026-10-09T13:44:08Z","modified":"2026-10-26T09:43:35.626505259Z","updated_at":"2026-11-02T15:43:50.599064Z"},{"id":"CLSA-2026-1791557610","title":"freerdp: Fix of 4 CVEs","description":"- CVE-2026-68580: reject a FramesPerPacket of INT32_MAX or more in audin_process_open() before it is stored, so a malicious server cannot overflow the per-packet size arithmetic in the audio input backends\n- CVE-2026-66402: return the real length of certificate ASN.1 strings and reject values that are not a host name or IP, so a certificate carrying an embedded NUL can no longer pass identity validation as a shorter, different name\n- CVE-2026-67300: deep-clone WINDOW_STATE_ORDER and NOTIFY_ICON_STATE_ORDER before posting them to the async update queue, and free the clone in the message destructor; the shallow copies referenced parser-owned heap released as soon as the callback returned\n- CVE-2026-67289: validate the server-supplied redirection fields - addresses must parse as IPv4/IPv6, FQDN and NetBIOS name must look like a host, username and domain must not contain line breaks - so CRLF in TargetNetAddress can no longer be injected into the HTTP proxy CONNECT request","status":"published","published":"2026-10-09T14:54:00Z","modified":"2026-10-26T09:43:47.837733556Z","updated_at":"2026-11-02T15:43:50.599064Z"}]}}