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high advisory

Jsrsasign Infinite Loop Vulnerability (CVE-2026-4598)

Jsrsasign versions before 11.1.1 are vulnerable to an infinite loop via the bnModInverse function when processing zero or negative inputs, potentially leading to a denial of service.

The jsrsasign library, a popular JavaScript library for implementing cryptography standards, is susceptible to a denial-of-service vulnerability. Specifically, versions prior to 11.1.1 are vulnerable to CVE-2026-4598, where the bnModInverse function within ext/jsbn2.js can enter an infinite loop when processing zero or negative inputs to the BigInteger.modInverse function. An attacker can exploit this by providing maliciously crafted values (e.g., modInverse(0, m) or `modInverse(-1…

Detection coverage 2

Detect Jsrsasign ModInverse Zero Input

high

Detects suspicious calls to jsrsasign's bnModInverse function with zero or negative inputs, indicative of CVE-2026-4598 exploitation.

sigma tactics: denial_of_service techniques: T1499.004 sources: webserver, linux

Detect Jsrsasign ModInverse Negative Input

high

Detects suspicious calls to jsrsasign's bnModInverse function with negative inputs, indicative of CVE-2026-4598 exploitation.

sigma tactics: denial_of_service techniques: T1499.004 sources: webserver, linux

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