wolfSSL up to 5.9.1 X.509 Certificate ParseCertRelative certificate validation

Summaryinfo

A vulnerability, which was classified as problematic, has been found in wolfSSL up to 5.9.1. This impacts the function ParseCertRelative of the component X.509 Certificate Handler. This manipulation causes certificate validation. This vulnerability appears as CVE-2026-55960. The attack may be initiated remotely. There is no available exploit. Applying a patch is the recommended action to fix this issue.

Detailsinfo

A vulnerability has been found in wolfSSL up to 5.9.1 and classified as problematic. Affected by this vulnerability is the function ParseCertRelative of the component X.509 Certificate Handler. 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:

Un-negotiated Raw Public Key (RFC 7250) accepted in place of an X.509 certificate, bypassing chain validation. A raw public key has no chain, so ParseCertRelative() accepts it without performing any trust verification; it must therefore only be accepted when RPK was actually negotiated for that peer. The check now defaults the expected type to X.509 (per RFC 7250/8446) when no type was negotiated, comparing against the received server certificate type on the client and the selected client certificate type on the server, and rejects any mismatch, including an un-negotiated raw public key, with UNSUPPORTED_CERTIFICATE. Only affects builds with Raw Public Key support (HAVE_RPK) enabled - disabled by default in a standalone build, but included in --enable-all.

The weakness was presented by Nvidia Project Vanessa. The advisory is shared at github.com. This vulnerability is known as CVE-2026-55960 since 06/18/2026. 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.

The vulnerability scanner Nessus provides a plugin with the ID 323816 (Linux Distros Unpatched Vulnerability : CVE-2026-55960), which helps to determine the existence of the flaw in a target environment.

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

The vulnerability is also documented in the vulnerability database at Tenable (323816). 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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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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