wolfSSL up to 5.9.1 wolfSSL_X509_verify_cert certificate validation

Summaryinfo

A vulnerability was found in wolfSSL up to 5.9.1. It has been classified as problematic. The impacted element is the function wolfSSL_X509_verify_cert. This manipulation causes certificate validation. The identification of this vulnerability is CVE-2026-11310. It is possible to initiate the attack remotely. There is no exploit available. Applying a patch is the recommended action to fix this issue.

Detailsinfo

A vulnerability was found in wolfSSL up to 5.9.1. It has been declared as problematic. Affected by this vulnerability is the function wolfSSL_X509_verify_cert. 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. The summary by CVE is:

X.509 trust-chain bypass in the OpenSSL compatibility certificate verifier (wolfSSL_X509_verify_cert()). This affects only builds with --enable-opensslextra (OPENSSL_EXTRA) and whose application validates certificates by calling X509_verify_cert() with caller-supplied untrusted intermediate certificates; for those users it is critical, otherwise the library is unaffected. In particular, native wolfSSL TLS/DTLS usage is not impacted. wolfSSL's X509_verify_cert() temporarily loads each caller-supplied untrusted intermediate into the certificate manager but failed to drop them before the trusted-store check, so an untrusted intermediate could anchor the path itself. An attacker can present a chain that never reaches a configured trust anchor and have it accepted, resulting in acceptance of an attacker-controlled certificate. This is certificate verification independent of TLS (e.g. S/MIME/CMS, code/firmware signing, JWT/JWS x5c), is not specific to any key type or algorithm, and a single untrusted intermediate suffices. The default wolfSSL TLS handshake (WOLFSSL_VERIFY_PEER) is not affected; only TLS applications doing manual or deferred peer verification through this API are, which also requires --enable-sessioncerts.

The weakness was shared by Corban Villa, Sohee Kim and Austin Chu. The advisory is shared at github.com. This vulnerability is known as CVE-2026-11310 since 06/04/2026. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1587.003 for this issue.

Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com.

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Name

• wolfSSL

Version

• 5.9.0
• 5.9.1

License

• open-source

Website

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

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