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Improper Authentication

CVE-2026-45363

Low
0/10

Summary

ruby-jwt versions prior to 3.2.0 improperly accept empty string or nil values as HMAC verification keys, allowing JWT signature verification to succeed with an attacker-forged token. Due to unsafe key handling in 'JWT.decode' and 'key_finder' logic, empty or nil keys are silently coerced and passed to 'OpenSSL::HMAC', which produces a valid digest under an empty key. This results in authentication bypass for HS256, HS384, and HS512 algorithms when applications rely on affected key resolution paths.

  • HIGH
  • NETWORK
  • HIGH
  • UNCHANGED
  • NONE
  • NONE
  • HIGH
  • NONE

CWE-287 - Improper Authentication

Improper (or broken) authentication attacks are widespread, and have accounted for many of the worst data breaches in recent years. Improper authentication attacks are a class of vulnerabilities where an attacker impersonates a legitimate user by exploiting weaknesses in either session management or credential management to gain access to the user’s account. This can result in disclosure of sensitive information, and can lead to system compromise, theft, identity theft, and fraud.

References

Advisory Timeline

  • Published