Division by zero Affecting jsrsasign package, versions <11.1.1
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JS-JSRSASIGN-15371176
- published22 Mar 2026
- disclosed21 Feb 2026
- creditKr0emer
Introduced: 21 Feb 2026
CVE-2026-4603 (opens in a new tab)How to fix?
Upgrade jsrsasign to version 11.1.1 or higher.
Overview
jsrsasign is a free pure JavaScript cryptographic library.
Affected versions of this package are vulnerable to Division by zero due to the RSASetPublic/KEYUTIL parsing path in ext/rsa.js and the BigInteger.modPowInt reduction logic in ext/jsbn.js. An attacker can force RSA public-key operations (e.g., verify and encryption) to collapse to deterministic zero outputs and hide “invalid key” errors by supplying a JWK whose modulus decodes to zero.