CVE-2026-91949 PUBLISHED

FreeRDP 3.0.0 through 3.30.0 Protocol Negotiation Bypass

Assigner: VulnCheck
Reserved: 15.09.2026 Published: 15.09.2026 Updated: 15.09.2026

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.

CVSS Vector: 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
CVSS Score: 9.2

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	High
Attack Complexity	Low	Integrity	Low	Integrity	Low
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N
CVSS Score: 9.3

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

CVSS 3.1

Product Status

Vendor	FreeRDP
Product	FreeRDP
Versions	Default: unaffected affected from 3.0.0 to 3.31.0 (excl.) Version 3.31.0 is unaffected

CVE-2026-91949 PUBLISHED

FreeRDP 3.0.0 through 3.30.0 Protocol Negotiation Bypass

Metrics

Product Status

Credits

References

Problem Types