Intel

AIKIDO-2026-10527

jsrsasign is vulnerable to Observable Timing Discrepancy

Observable Timing Discrepancy Pre-CVE
Found by Aikido Intel before public disclosure or CVE publication.
Published Apr 24, 2026

24

Low Risk

This Affects:

JSjsrsasign
4.10.0 - 11.1.2
Fixed in 11.1.3
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TL;DR

Observable timing discrepancies in HMAC-based JSON Web Signature verification in jsrsasign allowed signature comparisons to be performed using direct string equality rather than a constant-time routine. An attacker able to measure verification response times repeatedly could potentially infer valid signature bytes and forge HMAC-signed JWS tokens. Successful exploitation could result in authentication bypass, token forgery, or unauthorized access to protected resources relying on affected HS* signature verification paths.

Who does this affect?

You are affected if you are using a version that falls within the vulnerable range.

Background info

jsrsasign is vulnerable to Observable Timing Discrepancy in versions 4.10.0 - 11.1.2.

How to fix this

Upgrade the jsrsasign library to the patch version.