Cloudanix VulnDB

CVE-2026-9537

Medium · 5.3

CVSS

5.3

EPSS

0.3%

Published

Jul 17, 2026

CISA due date

—

The record

Mojo::JWT versions before 1.02 for Perl verify HMAC signatures with a non-constant-time string comparison. The decode() method compares the supplied signature to the recomputed HMAC with Perl's eq operator, which stops at the first differing byte, so the comparison time varies with the number of matching leading bytes. A caller that decodes attacker supplied tokens leaks the expected signature through this timing variation, which can be aggregated over many requests to recover the signature and forge a token.

Affected packages

Ecosystem Package Introduced Fixed

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