When an application enables both OCSP and CRL revocation checking on one WOLFSSL_CTX or certificate manager, wolfSSL skips the CRL check for any… (CVE-2026-94417)

The vulnerability occurs when an application enables both OCSP and CRL revocation checking on a single WOLFSSL_CTX or certificate manager in wolfSSL. If a peer certificate lacks an Authority Information Access OCSP URL, wolfSSL skips the CRL check, accepting certificates revoked in the loaded CRL. This is due to the soft-fail policy for missing OCSP responders, which treats 'no responder' as a successful OCSP check before deciding on CRL fallback. The flaw affects TLS 1.0 to TLS 1.3 and DTLS, impacting both client and server certificate verification, including mutual and post-handshake authentication. Unchecked intermediate certificates can be promoted to trusted signers, persisting trust beyond the current connection. The issue affects wolfSSL versions 5.9.2 and earlier, with specific configurations noted for versions 5.9.1 and 5.9.2.

The vulnerability allows wolfSSL to accept certificates that are revoked according to the loaded CRL if the certificate lacks an OCSP URL and both OCSP and CRL checks are enabled. This can lead to acceptance of revoked certificates, undermining certificate revocation checking and potentially allowing unauthorized certificate use. The unchecked intermediate certificates may remain trusted in long-running processes, increasing risk over time. The CVSS score is 5.3 (medium severity), indicating a moderate impact with limited attack complexity and no confidentiality or availability impact but with integrity impact.

No official patch or fix status is provided in the input data. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Applications should avoid enabling both OCSP and CRL revocation checking simultaneously on the same WOLFSSL_CTX or certificate manager until a fix is confirmed. Using OCSP stapling alone via wolfSSL_CTX_EnableOCSPStapling() is not affected. For long-running processes, if affected, the WOLFSSL_CTX should be torn down and recreated after updating the library to prevent continued trust of revoked intermediates.