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Vulnerability · Published Mar 27, 2026 · Assigned by GitHub_M

CVE-2026-33891Forge has Denial of Service via Infinite Loop in BigInteger.modInverse() with Zero Input

High 7.5

In plain English

A high-severity infinite loop in forge from digitalbazaar. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.6%top 50.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

Forge (also called `node-forge`) is a native implementation of Transport Layer Security in JavaScript. Prior to version 1.4.0, a Denial of Service (DoS) vulnerability exists in the node-forge library due to an infinite loop in the BigInteger.modInverse() function (inherited from the bundled jsbn library). When modInverse() is called with a zero value as input, the internal Extended Euclidean Algorithm enters an unreachable exit condition, causing the process to hang indefinitely and consume 100% CPU. Version 1.4.0 patches the issue.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Ubuntu:22.04:LTSnode-node-forgeno fix listedUBUNTU-CVE-2026-33891
npmnode-forge1.4.0GHSA-5m6q-g25r-mvwx

Affected products (as reported)

VendorProductVersions
digitalbazaar forge < 1.4.0

Weakness: CWE-835, CWE-606 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References