# 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.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-89134, GHSA-p2xv-vrwq-543q, UBUNTU-CVE-2026-89134

## 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 (Improper Certificate Validation)

## Which versions are affected by CVE-2026-89134?

It affects 1 product.


Products: 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

- [CVE-2024-5991](https://insights.sbomify.com/CVE-2024-5991/): Buffer overread in domain name matching (critical 10.0)
- [CVE-2021-37155](https://insights.sbomify.com/CVE-2021-37155/): Security feature bypass in n/a (critical 9.8)
- [CVE-2020-36177](https://insights.sbomify.com/CVE-2020-36177/): Memory corruption in n/a (critical 9.8)
- [CVE-2014-2896](https://insights.sbomify.com/CVE-2014-2896/): Memory corruption in n/a (critical 9.8)
- [CVE-2014-2897](https://insights.sbomify.com/CVE-2014-2897/): Memory corruption in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89134 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-89134 in the wild and no public exploit code.

Affected product: Wolfssl Wolfssl. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-89134/ (Markdown: https://insights.sbomify.com/CVE-2026-89134/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89134
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89134
- OSV: https://osv.dev/vulnerability/CVE-2026-89134

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89134/
Summaries are generated and may contain mistakes; the official description above is the record.