CVE-2026-67294
What it is
FreeRDP before 3.29.0 improperly validates the Extended Key Usage (EKU) purpose of the peer certificate during client-side server TLS authentication. In x509_utils_verify(), when server-purpose (X509_PURPOSE_SSL_SERVER) verification fails, the code falls back to client-purpose and any-purpose verification, so a trusted, hostname-matching certificate valid only for clientAuth can be accepted as the RDP server certificate. In environments relying on EKU separation between client and server certificates, this allows a clientAuth-only certificate issued by a trusted CA to bypass server certificate purpose validation.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.4% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Details
- Published
- Last modified
- Exploit probability
- 0.4% · EPSS, next 30 days
- Weakness
- CWE-295 · Improper certificate validation
- Record status
- Analyzed
Affected
- Freerdp < 3.29.0
Attack profile CVSS 4.0 · 9.3
- Attack vector
- Network
- Complexity
- Low
- Attack requirements
- None
- Privileges needed
- None
- User interaction
- None
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/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
Fix and advisories
- https://github.com/FreeRDP/FreeRDP/commit/f3b4347105114fe7453828736bea069999af319f
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-89c6-jjrw-96h4
- https://www.vulncheck.com/advisories/freerdp-before-tls-certificate-eku-bypass
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-89c6-jjrw-96h4
References
- https://github.com/FreeRDP/FreeRDP/commit/f3b4347105114fe7453828736bea069999af319f
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-89c6-jjrw-96h4
- https://www.vulncheck.com/advisories/freerdp-before-tls-certificate-eku-bypass
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-89c6-jjrw-96h4