CVE-2026-125336: Cert Validation Flaw (CVSS 7.4)

Description

Forge (also called node-forge) is a native implementation of Transport Layer Security in JavaScript. Prior to 1.4.3, pki.verifyCertificateChain() in lib/x509.js does not decode or enforce the X.509 nameConstraints extension while validating certificate paths. A name-constrained certificate authority with a non-critical extension can therefore issue a leaf certificate with a subjectAltName dNSName or subject commonName outside a permitted subtree or inside an excluded subtree, and node-forge accepts the chain. Exploitation requires a name-constrained CA that chains to a trusted root and either its private key or the ability to obtain an out-of-scope certificate, allowing impersonation of names outside the delegated namespace, including against forge.tls clients. Chains without nameConstraints are not affected, and affected versions safely reject critical nameConstraints as unsupported rather than accepting them. This issue is fixed in version 1.4.3.

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CVSS v3.1 Score

7.4

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0023

Probability of exploitation

0.14%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-295 CWE-295

References

Other References

https://github.com/digitalbazaar/forge/commit/6b23eae8beac316b6867bdb0e7ad7c2c959a97f6 https://github.com/digitalbazaar/forge/commit/862aa5f630bdf40b0dfda408d6ac357bf35a7d6b https://github.com/digitalbazaar/forge/pull/1169 https://github.com/digitalbazaar/forge/releases/tag/v1.4.3 https://github.com/digitalbazaar/forge/security/advisories/GHSA-3cc4-3294-vgjf

Frequently Asked Questions

What is CVE-2026-125336? +

Forge (also called node-forge) is a native implementation of Transport Layer Security in JavaScript. Prior to 1.4.3, pki.verifyCertificateChain() in lib/x509.js does not decode or enforce the X.509 nameConstraints extension while validating certificate paths. A name-constrained certificate authority with a non-critical extension can therefore issue a leaf certificate with a subjectAltName dNSName or subject commonName outside a permitted subtree or inside an excluded subtree, and node-forge accepts the chain. Exploitation requires a name-constrained CA that chains to a trusted root and either its private key or the ability to obtain an out-of-scope certificate, allowing impersonation of names outside the delegated namespace, including against forge.tls clients. Chains without nameConstraints are not affected, and affected versions safely reject critical nameConstraints as unsupported rather than accepting them. This issue is fixed in version 1.4.3. It has a CVSS v3.1 base score of 7.4 (HIGH).

How severe is CVE-2026-125336? +

CVE-2026-125336 has a CVSS v3.1 score of 7.4 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0023, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-125336? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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