{"id":"CVE-2026-91949","title":"FreeRDP server versions before 3.31.0 contain a protocol negotiation bypass vulnerability that allows unauthenticated attackers to establish RDSTLS connections despite server policy disabling them","summary":"FreeRDP server versions before 3.31.0 contain a protocol negotiation bypass vulnerability that allows unauthenticated attackers to establish RDSTLS connections despite server policy disabling them. Attackers can send incompatible protoco…","severity":"critical","cvss":9.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N","cwe":["CWE-693","CWE-358"],"vendor":"freerdp","product":"freerdp","affected":["freerdp >= 3.0.0, < 3.31.0"],"patched":["freerdp 3.31.0"],"published":"2026-09-15","updated":"2026-09-24","sourceUpdated":"2026-09-24T12:14:46.820","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-91949","references":[{"url":"https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-x7v6-xfx3-52j6","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/freerdp-3.0.0-through-3.30.0-protocol-negotiation-bypass","label":"disclosure@vulncheck.com"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-91949.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-91949"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2533925"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-91949"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-91949"},{"url":"https://access.redhat.com/errata/RHSA-2026:74471"},{"url":"https://access.redhat.com/errata/RHSA-2026:73979"}],"tags":["nvd","cve.org","csaf","vex","red-hat"],"epss":0.00578,"epssPercentile":0.4739,"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-09-17T19:15:27.791401Z"},"ingestedAt":"2026-09-15T15:39:12.919Z","slug":"CVE-2026-91949","body":"## Overview\n\nFreeRDP server versions before 3.31.0 contain a protocol negotiation bypass vulnerability that allows unauthenticated attackers to establish RDSTLS connections despite server policy disabling them. Attackers can send incompatible protocol requests, receive negotiation failures, then complete TLS handshake and enter RDSTLS to bypass pre-authentication transport restrictions.\n\n## Affected\n\n- `freerdp >= 3.0.0, < 3.31.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `freerdp 3.31.0`\n\n## Vendor advisories\n\n- **Red Hat VEX** · Critical · affected: Red Hat Enterprise Linux 10 · no fix planned: Red Hat Enterprise Linux 10 · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-91949.json)\n- **RHSA-2026:74471** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) · released 2026-10-01 · [advisory](https://access.redhat.com/errata/RHSA-2026:74471)\n- **RHSA-2026:73979** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · released 2026-10-02 · [advisory](https://access.redhat.com/errata/RHSA-2026:73979)","depth":"midnight","depthScore":51,"depthScoreParts":{"impact":51.2,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}