CVE-2026-67294

FreeRDP before 3.29.0 improperly validates the Extended Key Usage EKU purpose of the peer certificate during client-side server TLS authentication. In x509utilsverify, when server-purpose X509PURPOSESSLSERVER verification fails, the code falls back to client-purpose and any-purpose verification, ...

CVE-2026-67294

FreeRDP before 3.29.0 improperly validates the Extended Key Usage EKU purpose of the peer certificate during client-side server TLS authentication. In x509utilsverify, when server-purpose X509PURPOSESSLSERVER verification fails, the code falls back to client-purpose and any-purpose verification, ...

EUVD-2026-51842

FreeRDP before 3.29.0 improperly validates the Extended Key Usage EKU purpose of the peer certificate during client-side server TLS authentication. In x509utilsverify, when server-purpose X509PURPOSESSLSERVER verification fails, the code falls back to client-purpose and any-purpose verification, ...

CVE-2026-67294

FreeRDP prior to 3.29.0 is affected by an EKU bypass in TLS server verification. In x509_utils_verify(), when server-purpose (X509_PURPOSE_SSL_SERVER) validation fails, the code may fall back to client-purpose and any-purpose checks, allowing a certificate valid only for clientAuth to be treated ...

CVE-2026-67294 FreeRDP before 3.29.0 TLS Certificate EKU Bypass

FreeRDP before 3.29.0 improperly validates the Extended Key Usage EKU purpose of the peer certificate during client-side server TLS authentication. In x509utilsverify, when server-purpose X509PURPOSESSLSERVER verification fails, the code falls back to client-purpose and any-purpose verification, ...

CVE-2026-67294 FreeRDP before 3.29.0 TLS Certificate EKU Bypass

FreeRDP before 3.29.0 improperly validates the Extended Key Usage EKU purpose of the peer certificate during client-side server TLS authentication. In x509utilsverify, when server-purpose X509PURPOSESSLSERVER verification fails, the code falls back to client-purpose and any-purpose verification, ...

PYSEC-2026-3051 rfc3161-client Has Improper Certificate Validation

Summary An Authorization Bypass vulnerability in rfc3161-client's signature verification allows any attacker to impersonate a trusted TimeStamping Authority TSA. By exploiting a logic flaw in how the library extracts the leaf certificate from an unordered PKCS7 bag of certificates, an attacker ca...

EUVD-2026-36765

In OCaml-TLS before 2.1.0, the server implementation does insufficient checks of the certificate provided by the client when doing client authentication, which allows impersonation with certificates that are not meant for client authentication because of KeyUsage and ExtendedKeyUsage...

EUVD-2026-36764

In OCaml-TLS before 2.1.0, the client implementation does insufficient checks of the certificate provided by the server, which allows impersonation with certificates that are not meant for server authentication because of KeyUsage and ExtendedKeyUsage...

CVE-2026-45389

In OCaml-TLS before 2.1.0, the server implementation does insufficient checks of the certificate provided by the client when doing client authentication, which allows impersonation with certificates that are not meant for client authentication because of KeyUsage and ExtendedKeyUsage...

CVE-2026-45388

In OCaml-TLS before 2.1.0, the client implementation does insufficient checks of the certificate provided by the server, which allows impersonation with certificates that are not meant for server authentication because of KeyUsage and ExtendedKeyUsage...

CVE-2026-45389

In OCaml-TLS before 2.1.0, the server implementation does insufficient checks of the certificate provided by the client when doing client authentication, which allows impersonation with certificates that are not meant for client authentication because of KeyUsage and ExtendedKeyUsage...

CVE-2026-45388

In OCaml-TLS before 2.1.0, the client implementation does insufficient checks of the certificate provided by the server, which allows impersonation with certificates that are not meant for server authentication because of KeyUsage and ExtendedKeyUsage...

CVE-2026-45389

In OCaml-TLS before 2.1.0, the server implementation does insufficient checks of the certificate provided by the client when doing client authentication, which allows impersonation with certificates that are not meant for client authentication because of KeyUsage and ExtendedKeyUsage...

curl: curl GnuTLS backend accepts a clientAuth-only certificate for HTTPS server authentication

Summary: When curl/libcurl is built with the GnuTLS backend, the current HTTPS server-certificate validation path verifies the trust chain and hostname but does not enforce TLS server Extended Key Usage semantics. As a result, a leaf certificate that chains to a trusted CA, matches the requested...

OSEC-2026-07 TLS-server does insufficient client certificate checks (missing KeyUsage and ExtendedKeyUsage validation)

The TLS server implementation does not validate the KeyUsage and ExtendedKeyUsage extensions of client certificates when mutually authenticated TLS is requested. This can lead to impersonation with a certificate issued to a server. Scenario An operations engineer enables mTLS on the admin endpoin...

OSEC-2026-06 TLS-client (with TLS 1.3) does insufficient certificate checks (missing KeyUsage and ExtendedKeyUsage validation)

The ocaml-TLS 1.3 client does not validate the KeyUsage and ExtendedKeyUsage extensions of the server certificate. This can lead to impersonation with a certificate issued to a client. Scenario Every employee at a major bank carries a smart card. The card holds a clientAuth certificate issued by...

PT-2026-42203

Name of the Vulnerable Software and Affected Versions OCaml-TLS versions prior to 2.1.0 Description The server implementation fails to properly validate the KeyUsage and ExtendedKeyUsage extensions of certificates provided by clients during mutual TLS mTLS authentication. This allows an attacker ...

PT-2026-42202

Name of the Vulnerable Software and Affected Versions OCaml-TLS versions prior to 2.1.0 Description The client implementation in OCaml-TLS fails to properly validate the KeyUsage and ExtendedKeyUsage EKU extensions of server certificates during TLS 1.3 handshakes. Specifically, the answer...

curl: Schannel custom-CA path skips Extended Key Usage enforcement

Hi all, We believe the Schannel custom-CA verification path in lib/vtls/schannelverify.c may skip Extended Key Usage enforcement. In particular, a certificate that chains to the trusted custom CA but contains only id-kp-clientAuth, rather than id-kp-serverAuth, may pass peer verification on Windo...