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CVE-2026-89133

Status: AnalyzedMedium (6.3)—

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

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

Validación deficiente de certificados X.509 en wolfSSL permite falsificar certificados (CWE-295), explotable remotamente sin privilegios (AV:N/PR:N). Posibilita ataques MITM al aceptar certificados inválidos para dominios no autorizados.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Network SegmentationLimit Access to Resource Over NetworkFilter Network TrafficVulnerability ScanningUser TrainingPrivileged Account Management

Affected technologies (1)

Wolfssl — Wolfssl

CWEs

References

Raw JSON (NVD)

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  "id": "CVE-2026-89133",
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          "options": [
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          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
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  "published": "2026-09-27T10:16:58.900",
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