CVE-2026-9537
Last modified
CVE-2026-9537 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. 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.. EPSS estimates a 0.17% chance of exploitation in the next 30 days.
Description
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness Enumeration
Affected Software
Source: CNA advisory (CVE.org). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| JBERGER | Mojo::JWT | < 1.02 |
References
Timeline
- Published
- Last Modified
- Status
- Deferred
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