---
title: "CVE-2026-89134\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2026-89134?format=md
keywords: index, follow
---

# CVE-2026-89134

Publication date 29 September 2026

Last updated 30 September 2026

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

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## 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.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| wolfssl | 26.04 LTS resolute | Needs evaluation |
| 24.04 LTS noble | Needs evaluation |
| 22.04 LTS jammy | Needs evaluation |
| 20.04 LTS focal | Needs evaluation |
| 18.04 LTS bionic | Needs evaluation |
| 16.04 LTS xenial | Needs evaluation |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v4.0

**Base score**

6.3 · Medium

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | High |
  | Attack requirements | None |
  | Privileges required | None |
  | User interaction | None |
  | Vulnerable system - Confidentiality impact | Low |
  | Vulnerable system - Integrity impact | Low |
  | Vulnerable system - Availability impact | None |
  | Subsequent system - Confidentiality impact | None |
  | Subsequent system - Integrity impact | None |
  | Subsequent system - Availability impact | None |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 6.3 · Medium |
  | Base + Threat score | - |
  | Base + Environmental score | - |
  | Base + Threat + Environmental score | - |

**Vector:** 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

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-89134)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2026-89134)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2026-89134)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2026-89134)

### Other references

* <https://www.cve.org/CVERecord?id=CVE-2026-89134>
* <https://github.com/wolfSSL/wolfssl/pull/10837 (v5.9.4-stable)>
* <https://github.com/wolfSSL/wolfssl/pull/10837>