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CVE-2026-91949

CRITICALCVSS 9.3/10EPSS 0.45%

Last modified

CVE-2026-91949 is a critical-severity vulnerability rated 9.3/10 on the CVSS scale. 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.. EPSS estimates a 0.45% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
9.3/10

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

CVSS 4.0
9.2/10

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
0.45%

38.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
FreeRDPFreeRDP>= 3.0.0, < 3.31.0

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

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.
How severe is CVE-2026-91949?
CVE-2026-91949 has a CVSS score of 9.3/10 (CRITICAL severity). The EPSS model estimates a 0.45% probability of exploitation in the next 30 days.
How do I fix CVE-2026-91949?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST