NameConstraints not enforced across unconstrained intermediate CA (CVE-2026-89133) | HOL Guard CVE

Medium · CVSS 6.3CVE-2026-89133

NameConstraints not enforced across unconstrained intermediate CA

Answer in brief

CVE-2026-89133 records a Medium severity (CVSS 6.3) vulnerability in NameConstraints not enforced across unconstrained intermediate CA. The current sources do not mark it as known exploited. The current feed maps wolfSSL/wolfSSL (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 27, 2026Updated Sep 27, 2026Source checked Sep 27, 2026First seen by HOL Sep 27, 2026Material review Sep 27, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.3
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 6.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps wolfSSL/wolfSSL (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
wolfSSL/wolfSSLgeneric	>=0 <=5.9.2	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for wolfSSL/wolfSSL.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Sep 27, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 27, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 27, 2026

Sources and claim methodology

GitHub security advisorygithub.com

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.