CVE-2026-9537

Name of the Vulnerable Software and Affected Versions Mojo::JWT versions prior to 1.02

Description The decode() method verifies HMAC signatures using a non-constant-time string comparison via Perl's eq operator. Because this operator stops at the first differing byte, the time taken for the comparison varies based on the number of matching leading bytes. An attacker can exploit this timing variation over multiple requests to recover the expected signature and forge a token.

Recommendations Update Mojo::JWT to version 1.02 or later.