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Low · 2.3 CVE-2026-94417 EUVD-2026-87908GHSA-vqr9-9vw2-33w6

CRL check skipped when OCSP enabled and certificate has no OCSP URL

Published Sep 27, 2026 · Updated Sep 29, 2026 · Assigned by wolfSSL

Description

When an application enables both OCSP and CRL revocation checking on one WOLFSSL_CTX or certificate manager, wolfSSL skips the CRL check for any peer certificate that carries no Authority Information Access OCSP URL, and accepts a certificate the loaded CRL lists as revoked. The soft-fail policy for a missing responder collapses the OCSP result onto success before the code decides whether the CRL fallback is still needed, so "no responder exists" becomes indistinguishable from "the responder answered good". Affected builds define both HAVE_OCSP and HAVE_CRL: --enable-ocsp --enable-crl directly, and implicitly --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. An application is affected only if it calls both wolfSSL_CTX_EnableOCSP() (or wolfSSL_EnableOCSP() / wolfSSL_CertManagerEnableOCSP()) and wolfSSL_CTX_EnableCRL() (or the equivalents) with a CRL loaded; an application that uses OCSP stapling alone through wolfSSL_CTX_EnableOCSPStapling() is not affected, because that sets up a separate OCSP instance. The defect sits in ProcessPeerCerts() and is reachable over TLS 1.0 through TLS 1.3 and DTLS, both on a client verifying a server certificate and on a server verifying a client certificate under mutual or post-handshake authentication. When the skipped check falls on a chain certificate rather than the leaf, the unchecked intermediate is promoted into the certificate manager and stays a trusted signer for every later connection on that context, so an affected long-running process needs its WOLFSSL_CTX torn down and not only its library replaced. All wolfSSL versions from 5.9.2 and earlier are affected; on versions 5.9.1 and 5.9.2 the WOLFSSL_OCSP_CHECKALL configuration fails closed with OCSP_NEED_URL, which leaves wolfSSL_CTX_EnableOCSP() without CHECKALL as the exposed configuration on 5.9.2.

Affected products

VendorProductAffectedFixed
wolfSSL wolfSSL ≤ 5.9.2 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 13 wolfssl No fix yet —
Debian 12 wolfssl No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 wolfssl No fix yet —
Ubuntu 26.04 LTS wolfssl No fix yet —
Ubuntu 24.04 LTS wolfssl No fix yet —
Ubuntu 22.04 LTS wolfssl No fix yet —
Ubuntu 20.04 LTS wolfssl No fix yet —
Show 2 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 18.04 LTS wolfssl No fix yet —
Ubuntu 16.04 LTS wolfssl No fix yet —
ReleasePackageFixed inAdvisory
Alpine v3.24 wolfssl 5.9.4-r0 —

Azure Linux

ReleasePackageFixed inAdvisory
Azure Linux 3 mariadb No fix yet —

References