Vulnerability in Freerdp
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.3 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N.
EPSS exploit prediction
EPSS: 0.006 (47.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 47.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: +0.000
Affected products
Weakness classification (CWE)
References
- github.com/FreeRDP/FreeRDP/security/advisories/GHSA-x7v6-xfx3-52j6 (Exploit, vendor-advisory, Mitigation, Vendor Advisory)
- www.vulncheck.com/advisories/freerdp-3.0.0-through-3.30.0-protocol-negotiation-… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-91949?
- CVE-2026-91949 is a critical-severity vulnerability in Freerdp, classified under Protection Mechanism Failure. CVSS score: 9.3/10. Published 2026-09-15.
- How severe is CVE-2026-91949?
- Critical severity. CVSS v3 base score is 9.3 out of 10.