CVE-2026-85393
Received Received - Intake

node-forge RSA PKCS#1 v1.5 Signature Forgery via DigestAlgorithm Sequence Manipulation

Publication date: 2026-09-03

Last updated on: 2026-09-03

Assigner: VulnCheck

Description
node-forge through 1.4.0 fails to validate element count in nested DigestAlgorithm sequences during RSA PKCS#1 v1.5 signature verification. Attackers can embed garbage bytes inside the DigestAlgorithm sequence to forge valid signatures for arbitrary messages using low-exponent RSA keys. This is an incomplete fix for CVE-2026-33894.

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Meta Information

Published
2026-09-03
Last Modified
2026-09-03
Generated
2026-09-04
AI Q&A
2026-09-03
EPSS Evaluated
N/A
NVD
CVE-2026-85393
EUVD
EUVD-2026-70670

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
node-forge node-forge to 1.4.0 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-347 The product does not verify, or incorrectly verifies, the cryptographic signature for data.

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Executive Summary

node-forge through 1.4.0 fails to validate element count in nested DigestAlgorithm sequences during RSA PKCS#1 v1.5 signature verification. Attackers can embed garbage bytes inside the DigestAlgorithm sequence to forge valid signatures for arbitrary messages using low-exponent RSA keys.

Detection Guidance

To detect this vulnerability, inspect applications using node-forge version 1.4.0 or earlier. Check for improper ASN.1 parsing in RSA PKCS#1 v1.5 signatures. Review logs for unexpected signature validation failures or memory corruption errors in cryptographic operations. Use static analysis tools to scan for vulnerable library versions.

Impact Analysis

Attackers could forge valid digital signatures, potentially allowing them to impersonate users, alter data integrity, or bypass authentication mechanisms in systems relying on node-forge for RSA PKCS#1 v1.5 signature verification.

Compliance Impact

This vulnerability could undermine data integrity and authentication controls required by GDPR and HIPAA, potentially leading to non-compliance due to unauthorized data access or tampering. Systems using node-forge for signatures may fail to meet regulatory requirements for secure authentication.

Mitigation Strategies

Update node-forge to the latest version beyond 1.4.0 to ensure the fix for this vulnerability is applied. Review RSA PKCS#1 v1.5 signature verification processes in your applications to confirm proper validation of DigestAlgorithm sequences.

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