CVE-2026-91949 (CVSS 9.3)

Description

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.

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CVSS v3.1 Score

9.3

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N

EPSS — Exploit Prediction

0.0045

Probability of exploitation

0.38%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-693 CWE-693

References

Other References

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-x7v6-xfx3-52j6 https://www.vulncheck.com/advisories/freerdp-3.0.0-through-3.30.0-protocol-negotiation-bypass

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 9.3 (CRITICAL).

How severe is CVE-2026-91949? +

CVE-2026-91949 has a CVSS v3.1 score of 9.3 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0045, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-91949? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-91949