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CVE-2026-91949 (GCVE-0-2026-91949)

Vulnerability from cvelistv5 – Published: 2026-09-15 15:18 – Updated: 2026-09-17 19:28
VLAI
Title
FreeRDP 3.0.0 through 3.30.0 Protocol Negotiation Bypass
Summary
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.
Severity
9.2 (Critical)
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
9.3 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-17 19:15 UTC
CWE
  • CWE-693 - Protection Mechanism Failure
Assigner
References
Impacted products
Vendor Product Version CPE status
FreeRDP FreeRDP Affected: 3.0.0 , < 3.31.0 (semver)
Unaffected: 3.31.0 (semver)
    cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*
Create a notification for this product.
Date Public
2026-09-01 00:00
Credits
sam4k
Show details on NVD website
To clipboard 

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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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