CVE-2026-89133

NameConstraints not enforced across unconstrained intermediate CA

MEDIUM
5.3
CVSS Score
Published: September 27, 2026 at 09:18 AM UTC
Updated: October 2, 2026 at 06:58 PM UTC
1 product affected across 1 vendorwolfSSL

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v ≤ 5.9.2

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

Issue Tracking
Source: cverecord
https://github.com/wolfSSL/wolfssl/pull/10687

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-295

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