node-forge through 1.4.0 RSA PKCS#1 v1.5 Signature Forgery via Nested DigestAlgorithm Padding

Advisories

node-forge through 1.4.0 RSA PKCS#1 v1.5 Signature Forgery via Nested DigestAlgorithm Padding

severity: high
date: 9/3/2026
Affecting: forge <= 1.4.0
CVE: CVE-2026-85393
CWE: CWE-347 Improper Verification of Cryptographic Signature
CVSS: 8.7
CVSS V4 Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
References: GitHub Issue #1149
https://github.com/digitalbazaar/forge
https://github.com/digitalbazaar/forge/blob/v1.4.0/lib/rsa.js
https://github.com/digitalbazaar/forge/blob/v1.4.0/lib/asn1.js
GitHub Security Advisory (GHSA-ppp5-5v6c-4jwp)
Credit: George Chen
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.

Ready to get Started?

Explore VulnCheck, a next-generation Cyber Threat Intelligence platform, which provides exploit and vulnerability intelligence to help you prioritize and remediate vulnerabilities that matter.

Vulnerability Prioritization
Prioritize vulnerabilities that matter based on the threat landscape and defer vulnerabilities that don't.
Early Warning System
Real-time alerting of changes in the vulnerability landscape so that you can take action before the attacks start.

Schedule a Demo