Medium 6.3Published Sep 27, 2026

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

Updated under an hour ago (2026-10-19 09:00 UTC)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

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.

CVSS: 6.3 MEDIUM (v4.0, CNA)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
Weakness (CWE): CWE-295
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: wolfSSL
NVD analysis: Analyzed
Record last updated: Sep 29, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

wolfSSL wolfSSL wolfssl:wolfssl (from the name)	through 5.9.2	CNA record
wolfssl wolfssl wolfssl:wolfssl	through 5.9.2	NVD

References

https://github.com/wolfSSL/wolfssl/pull/10687issue-tracking

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.