wolfSSL up to 5.9.2 Trust Peer Certificate certificate validation

Summaryinfo

A vulnerability, which was classified as problematic, was found in wolfSSL up to 5.9.2. Affected is the function wolfSSL_CTX_trust_peer_cert/wolfSSL_trust_peer_cert of the component Trust Peer Certificate. Executing a manipulation can lead to certificate validation. This vulnerability is registered as CVE-2026-93302. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability classified as problematic was found in wolfSSL up to 5.9.2. This vulnerability affects the function wolfSSL_CTX_trust_peer_cert/wolfSSL_trust_peer_cert of the component Trust Peer Certificate. The manipulation with an unknown input leads to a certificate validation vulnerability. The CWE definition for the vulnerability is CWE-295. The product does not validate, or incorrectly validates, a certificate. As an impact it is known to affect integrity. CVE summarizes:

MatchTrustedPeer ignores the public key used, leading to forged CA clones passing verification. Affected builds are any that enable the macro WOLFSSL_TRUST_PEER_CERT and load CA certificates with wolfSSL_CTX_trust_peer_cert() or wolfSSL_trust_peer_cert(). The peer must know the certificates being loaded to either of those APIs to take advantage of the issue. When OPENSSL_COMPATIBLE_DEFAULTS is also defined this widens the affected API to include all CA certificate loading. Both macros are defined when using autoconf builds such as (nginx, haproxy, stunnel, wpas, apache httpd, hitch, bind, rsyslog, ffmpeg, all, distro). When the certificate is listed as a trusted peer certificate the issue previously allowed for a malicious (D)TLS server to bypass authentication once knowing which CA’s the client would accept. This also affects mutual authentication cases where the client knows which CA’s the server has loaded. If building with any of these configurations and using (D)TLS where the loaded CA’s could be known and authentication of the peer is desired, users should either: update to the latest wolfSSL version, apply the fix patch, or use the configure flag --disable-openssl-compatible-defaults and not load CA’s with wolfSSL_CTX_trust_peer_cert() or wolfSSL_trust_peer_cert() to mitigate the issue.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-93302 since 09/17/2026. The exploitation appears to be difficult. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/27/2026). The MITRE ATT&CK project declares the attack technique as T1587.003.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Name

• wolfSSL

Version

• 5.9.0
• 5.9.1
• 5.9.2

License

• open-source

Website

• Product: https://github.com/wolfSSL/wolfssl/

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