CVE-2026-4603
Medium
Description
Versions of the package jsrsasign before 11.1.1 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.
SeverityMedium
CVSS5.9
Exploit probability—
ProductKjur Jsrsasign
PublishedMar 23, 2026
First seenMar 23, 2026
Weakness typeCWE-369CWE-369
How to fix
Update
- kjur jsrsasign11.1.1 or later
- jsrsasign11.1.1 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| kjur jsrsasign | v < 11.1.1 | 11.1.1 |
| jsrsasignnpm | v < 11.1.1 | 11.1.1 |
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