by Kastro
Paper/Archive/CVE-2026-67294

CVE-2026-67294

FreeRDP FreeRDP — FreeRDP before 3.29.0 TLS Certificate EKU Bypass

EPSS 0.4%public exploitCVSS 9.3
critical.is priorityof 100
44
CVSS 9.3 (CNA)9.3 / 10 × 3027.9Not in CISA KEV+300.0EPSS percentile 30.1.301 × 206.0Exploit: SSVC poc+1010.0SSVC exploitation: poc+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
FreeRDP< 3.29.03.29.0CNA

Scores by source

VulnCheck (CNA)9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
VulnCheck (CNA)5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
CISA ADPSSVCExploitation: poc · Automatable: no · Technical impact: partial

References

exploitgithub.com/FreeRDP/FreeRDP/security/advisories/GHSA-89c6-jjrw-96h4patchgithub.com/FreeRDP/FreeRDP/commit/f3b4347105114fe7453828736bea069999af319fwriteupvulncheck.com/advisories/freerdp-before-tls-certificate-eku-bypass