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CRITICAL

CVE-2026-91949

CVSS v3

9.3

CRITICAL

EPSS Score

0.6 %

exploit probability, as of 2026-09-28

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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.

Technical details

Published
2026-09-15
Last Modified
2026-09-16

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.

Is CVE-2026-91949 actively exploited?

Active exploitation of CVE-2026-91949 has not been confirmed. Its EPSS score was 0.6% on 2026-09-28, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-91949?

CVE-2026-91949 has a CVSS v3 base score of 9.3 (CRITICAL severity).

Is CVE-2026-91949 affecting your environment?

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