When a wolfSSL application enables both OCSP and CRL revocation checks in the same context, the library incorrectly skips the CRL verification for certificates that lack an OCSP URL in the Authority Information Access extension. The library’s soft‑fail handling for a missing OCSP responder collapses the result to success before evaluating whether a CRL fallback should occur, causing a revoked certificate in the loaded CRL to be accepted as valid. This weakness allows an attacker to use a revoked certificate without detection and can lead to the promotion of a formerly checked intermediate certificate into the trusted signer pool for the lifetime of the context, thereby compromising long‑running processes. The flaw affects any TLS 1.0–1.3 or DTLS connection on both client and server sides under mutual or post‑handshake authentication, including configurations that use OCSP stapling alone, which is unaffected.

The issue exists in all wolfSSL releases up to and including 5.9.2. It only manifests when the application calls both wolfSSL_CTX_EnableOCSP() (or its equivalents) and wolfSSL_CTX_EnableCRL() (or equivalents) with a CRL loaded into the context. The affected build flags include both HAVE_OCSP and HAVE_CRL or any configuration that enables all features such as --enable-all, --enable-distro, --enable-curl, --enable-nginx, --enable-haproxy, --enable-stunnel, --enable-lighty, --enable-wpas, --enable-strongswan, --enable-mosquitto, --enable-jni, --enable-openvpn and --enable-krb.

The CVSS score of 2.3 indicates low severity. The EPSS score is not available, and the vulnerability is not listed in the CISA KEV catalog. Exploitation requires an application that has both OCSP and CRL checks enabled and a loaded CRL that lists a revoked certificate. The vulnerability can be triggered over any TLS 1.0–1.3 or DTLS connection, but because it depends on application configuration rather than an external attacker’s ability to inject traffic, the likelihood of exploitation is limited. Nonetheless, the flaw’s potential to promote revoked or intermediate certificates into the trusted pool can lead to long‑term compromise of all future connections using the same context.