Forge: Denial of Service via infinite loop in BigInteger.modInverse() with negative input (incomplete fix of CVE-2026-33891)
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 1.4.1
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Forge (node-forge), a JavaScript implementation of Transport Layer Security and related cryptographic functions, is affected before version 1.4.1. An attacker who can control the RSA public exponent used in key generation, or the input to its BigInteger modInverse function, could cause the Node.js process to hang at full CPU usage, denying service to other users.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original description
Forge (also called node-forge) is a native implementation of Transport Layer Security in JavaScript. Prior to 1.4.1, the affected implementation used BigInteger.prototype.modInverse(), bnModInverse(), lib/jsbn.js, RSA public exponent e to process the relevant input or security decision. node-forge's bundled jsbn implementation entered an infinite loop when BigInteger.prototype.modInverse() received a negative value or modulus. An attacker who could control the RSA public exponent passed to key generation, or a direct modInverse() operand, could block the Node.js event loop at full CPU. Parsed DER, PEM, JWK, PKCS#12, X.509, and TLS values are unsigned and cannot trigger this issue. This issue is fixed in version 1.4.1.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- digitalbazaar forge
fixed in 1.4.1