CVE-2026-67294 PUBLISHED

FreeRDP before 3.29.0 TLS Certificate EKU Bypass

Assigner: VulnCheck
Reserved: 29.07.2026 Published: 01.08.2026 Updated: 01.08.2026

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.

Metrics

CVSS 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
CVSS Score: 9.3

Product Status

Vendor FreeRDP
Product FreeRDP
Versions Default: unaffected
  • affected from 0 to 3.29.0 (excl.)
  • Version 3.29.0 is unaffected

Credits

  • 1121984919 reporter

References

Problem Types

  • Improper Certificate Validation CWE