CVE-2026-89134

What it is

A certificate with no dNSName SAN but another SAN type present (e.g. registeredID or iPAddress) bypassed the Subject CN dNSName name-constraint check. The CN-as-DNS fallback was gated on cert->subjectCN != NULL && cert->altNames == NULL && !cert->isCA instead of "no dNSName SAN", so an out-of-scope CN was accepted. This incomplete fix from CVE-2026-6731, leading to the name-constraint check issue, was introduced in wolfSSL version 5.9.2.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-09-27 10:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-02 18:57 UTC Last updatedMost recent change to the record

Details

Published

2026-09-27 10:16 UTC

Last modified

2026-10-02 18:57 UTC

Exploit probability

0.2% · EPSS, next 30 days

Weakness

CWE-295 · Improper certificate validation

Record status

Analyzed

Affected

• Wolfssl 5.9.2

Attack profile CVSS 4.0 · 6.3

Attack vector

Network

Complexity

High

Attack requirements

None

Privileges needed

None

User interaction

None

Confidentiality

Low

Integrity

Low

Availability

None