CVE-2026-89134 Subject CN name-constraint check bypassed when non-DNS SAN present
Attackers can bypass TLS name constraints by using non-DNS SANs, allowing acceptance of out-of-scope certificates in wolfSSL.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-89134?
CVE-2026-89134 is a medium-severity vulnerability in Wolfssl Wolfssl, published on 27 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-295
Which versions are affected by CVE-2026-89134?
It affects 1 product.
Products include Wolfssl Wolfssl.
How do I fix CVE-2026-89134?
No fix has been published for CVE-2026-89134 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-89134 being exploited?
There is no known exploitation of CVE-2026-89134 in the wild and no public exploit code.
Other vulnerabilities in Wolfssl Wolfssl
Sources
Also known as DEBIAN-CVE-2026-89134, GHSA-p2xv-vrwq-543q, UBUNTU-CVE-2026-89134.