⬆️ Upgrade dependency jwt to v2.10.3 [SECURITY]

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
jwt (changelog)	2.10.2 → 2.10.3

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ruby-jwt: Empty-key HMAC bypass; cross-language sibling of CVE-2026-44351

CVE-2026-45363 / GHSA-c32j-vqhx-rx3x

More information

Details

JWT.decode(token, '', true, algorithm: 'HS256') accepts an attacker-forged token.
OpenSSL::HMAC.digest('SHA256', '', payload) returns a valid digest under an empty key, and no raise InvalidKeyError if key.empty? precondition exists in the HMAC algorithm.

JWT.decode(token, "", true, algorithm: 'HS256')
  -> JWA::Hmac.verify(verification_key: "", ...)
  -> OpenSSL::HMAC.digest('SHA256', "", signing_input) == signature

The same path is reached when a keyfinder block or key_finder: argument returns "", nil, or an
array containing nil for an unknown key. JWT::Decode#find_key only rejects literal nil and empty
arrays, and JWT::JWA::Hmac silently coerces nil to "" (signing_key ||= '') before signing.

JWT.decode(token, nil, true, algorithms: ['HS256']) { |_h| "" }
  -> find_key returns ""               # "" && !Array("").empty? == true
  -> JWA::Hmac.verify(verification_key: "", ...)
  -> verifies

Common application patterns that produce the unsafe value: redis.get("kid:#{kid}").to_s, ORM string columns with default: '', ENV['SECRET'] || '', Hash.new('') lookups, [primary, fallback] where fallback may be nil. Applications passing a non-empty static key:, or whose keyfinder returns nil / raises on miss, are not affected.

The existing enforce_hmac_key_length option would block this but defaults to false. On OpenSSL ≥ 3.5 the empty-key HMAC.digest call no longer raises, so the OpenSSL-3.0 rescue in JWA::Hmac#sign does not fire.

Affects HS256/HS384/HS512 via both JWT.decode (positional key and block keyfinder) and
JWT::EncodedToken#verify_signature!(key_finder:)

Severity

• CVSS Score: 7.4 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References

• https://github.com/jwt/ruby-jwt/security/advisories/GHSA-c32j-vqhx-rx3x
• https://github.com/jwt/ruby-jwt/commit/db560b769a07bd9724e77ff505011ac01872106f
• https://github.com/jwt/ruby-jwt/releases/tag/v3.2.0
• https://github.com/jwt/ruby-jwt/issues/724
• https://github.com/jwt/ruby-jwt/releases/tag/v2.10.3
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/jwt/CVE-2026-45363.yml
• https://www.cve.org/CVERecord?id=CVE-2026-45363
• https://github.com/advisories/GHSA-c32j-vqhx-rx3x

This data is provided by the GitHub Advisory Database (CC-BY 4.0).

---

ruby-jwt: Empty-key HMAC bypass; cross-language sibling of CVE-2026-44351

CVE-2026-45363 / GHSA-c32j-vqhx-rx3x

More information

Details

JWT.decode(token, '', true, algorithm: 'HS256') accepts an attacker-forged token.
OpenSSL::HMAC.digest('SHA256', '', payload) returns a valid digest under an empty key, and no raise InvalidKeyError if key.empty? precondition exists in the HMAC algorithm.

JWT.decode(token, "", true, algorithm: 'HS256')
  -> JWA::Hmac.verify(verification_key: "", ...)
  -> OpenSSL::HMAC.digest('SHA256', "", signing_input) == signature

The same path is reached when a keyfinder block or key_finder: argument returns "", nil, or an
array containing nil for an unknown key. JWT::Decode#find_key only rejects literal nil and empty
arrays, and JWT::JWA::Hmac silently coerces nil to "" (signing_key ||= '') before signing.

JWT.decode(token, nil, true, algorithms: ['HS256']) { |_h| "" }
  -> find_key returns ""               # "" && !Array("").empty? == true
  -> JWA::Hmac.verify(verification_key: "", ...)
  -> verifies

Common application patterns that produce the unsafe value: redis.get("kid:#{kid}").to_s, ORM string columns with default: '', ENV['SECRET'] || '', Hash.new('') lookups, [primary, fallback] where fallback may be nil. Applications passing a non-empty static key:, or whose keyfinder returns nil / raises on miss, are not affected.

The existing enforce_hmac_key_length option would block this but defaults to false. On OpenSSL ≥ 3.5 the empty-key HMAC.digest call no longer raises, so the OpenSSL-3.0 rescue in JWA::Hmac#sign does not fire.

Affects HS256/HS384/HS512 via both JWT.decode (positional key and block keyfinder) and
JWT::EncodedToken#verify_signature!(key_finder:)

Severity

• CVSS Score: 7.4 / 10 (High)
• Vector String: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References

• https://github.com/jwt/ruby-jwt/security/advisories/GHSA-c32j-vqhx-rx3x
• https://github.com/jwt/ruby-jwt/issues/724
• https://github.com/jwt/ruby-jwt/commit/db560b769a07bd9724e77ff505011ac01872106f
• https://github.com/jwt/ruby-jwt
• https://github.com/jwt/ruby-jwt/releases/tag/v2.10.3
• https://github.com/jwt/ruby-jwt/releases/tag/v3.2.0
• https://github.com/rubysec/ruby-advisory-db/blob/master/gems/jwt/CVE-2026-45363.yml
• https://www.cve.org/CVERecord?id=CVE-2026-45363

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

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Release Notes

jwt/ruby-jwt (jwt)

v2.10.3: jwt-2.10.3

Compare Source

v2.10.3 (2026-05-22)

Full Changelog

Fixes and enhancements:

• Backport: Reject nil and empty HMAC keys when signing and verifying (CVE-2026-45363 / GHSA-c32j-vqhx-rx3x) #​725 (@​royzwambag)

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