# CVE-2026-89133: NameConstraints not enforced across unconstrained intermediate CA

> wolfSSL fails to enforce NameConstraints across unconstrained intermediate CAs, allowing attackers to bypass certificate validation restrictions.

- **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:** AZL-105176, DEBIAN-CVE-2026-89133, GHSA-vrp7-vcfx-j447, UBUNTU-CVE-2026-89133

## What is CVE-2026-89133?

CVE-2026-89133 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

wolfSSL versions 5.9.2 and earlier contain a flaw in the X.509 certificate validation logic where it fails to properly enforce NameConstraints extensions when there is an unconstrained CA tier between a name-constrained intermediate CA and the leaf certificate. wolfSSL incorrectly accepted certificates for hostnames they shouldn't be allowed to cover, due to a chain-walking state-machine bug that resets the validation state when encountering an intermediate without NameConstraints, thereby bypassing cryptographic delegation controls. This defect exists in the default build configuration that makes use of certificates where name constraint extensions are used. Thanks to Jack Lloyd, PathDiff, and Ben Smyth for reporting the issue.

Weakness: CWE-295 (Improper Certificate Validation)

## Which versions are affected by CVE-2026-89133?

It affects 1 product.


Products: Wolfssl Wolfssl.

## How do I fix CVE-2026-89133?

No fix has been published for CVE-2026-89133 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-89133 being exploited?

There is no known exploitation of CVE-2026-89133 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-2026-89133 and fix it if it is affected.

What it is: CVE-2026-89133 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-2026-89133 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-2026-89133/ (Markdown: https://insights.sbomify.com/CVE-2026-89133/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89133
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89133
- OSV: https://osv.dev/vulnerability/CVE-2026-89133

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89133/
Summaries are generated and may contain mistakes; the official description above is the record.