FreeRDP 3.0.0 through 3.30.0 Protocol Negotiation Bypass

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-91949
StatePUBLISHED
AssignerVulnCheck
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-15 16:17:48 UTC
Updated2026-09-15 16:17:48 UTC
DescriptionFreeRDP 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.

Risk And Classification

Primary CVSS: v4.0 9.2 CRITICAL from [email protected]

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

Problem Types: CWE-693 | CWE-693 Protection Mechanism Failure

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary9.2CRITICALCVSS: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/C...
4.0CNACVSS9.2CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N
3.1[email protected]Primary9.3CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
3.1CNACVSS9.3CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
High
Integrity
Low
Availability
None
Sub Conf.
High
Sub Integrity
Low
Sub Availability
None

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

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA FreeRDP FreeRDP affected 3.0.0 3.31.0 semver Not specified
CNA FreeRDP FreeRDP unaffected 3.31.0 semver Not specified

References

ReferenceSourceLinkTags
github.com/FreeRDP/FreeRDP/security/advisories/GHSA-x7v6-xfx3-52j6 [email protected] github.com
www.vulncheck.com/advisories/freerdp-3.0.0-through-3.30.0-protocol-negotiation-... [email protected] www.vulncheck.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: sam4k (en)

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