Improper Authentication Affecting jwt package, versions <3.2.0
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Test your applications- Snyk IDSNYK-RUBY-JWT-16755447
- published19 May 2026
- disclosed18 May 2026
- creditSnailSploit | Kai Aizen
Introduced: 18 May 2026
NewCVE-2026-45363 (opens in a new tab)Common Vulnerabilities and Exposures (CVE) are common identifiers for publicly known security vulnerabilities
Common Weakness Enumeration (CWE) is a category system for software weaknesses
Common Weakness Enumeration (CWE) is a category system for software weaknesses
How to fix?
Upgrade jwt to version 3.2.0 or higher.
Overview
Affected versions of this package are vulnerable to Improper Authentication in the signing and verification logic before applying JWT.decode. An attacker can forge valid JWTs by supplying a crafted token that passes signature verification due to the acceptance of empty keys.
Note: This is only exploitable if the application passes an empty string as the key, or if the keyfinder returns an empty string, nil, or an array containing nil for unknown keys, and the enforce_hmac_key_length option is not enabled.