Improper Certificate Validation in wolfSSL - CVE-2026-89133
Published: October 5, 2026
Vulnerability identifier: #VU153285
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-89133
CWE-ID: CWE-295
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to use certificates for unauthorized hostnames.
The vulnerability exists due to improper certificate validation in X.509 NameConstraints processing when validating a certificate chain with an unconstrained intermediate CA. A remote attacker can present a certificate chain for an unauthorized hostname to use certificates for unauthorized hostnames.
The issue affects certificate validation where name constraint extensions are used.
Affected software
wolfSSL
How to mitigate CVE-2026-89133
Install security update from vendor's website.
wolfSSL - update to 5.9.4