CVE-2026-91949
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 protocol requests, receive negotiation failures, then complete TLS handshake and enter RDSTLS to bypass pre-authentication transport restrictions.
Scoring
- Severity
- CRITICAL
- CVSS base score
- 9.3
- CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N
- EPSS probability
- 0.45%
- CWE
- CWE-693
- Published
- 2026-09-15
- Last modified
- 2026-09-15
Affected products
- FreeRDP FreeRDP
- FreeRDP FreeRDP
Weakness type
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