ruby-jwt is a Ruby implementation of the RFC 7519 OAuth JSON Web Token standard. Prior to 2.10.3 and 3.2.0, JWT.decode(token, '', true, algorithm: 'HS256') accepts an attacker-forged token because OpenSSL::HMAC.digest('SHA256', '', payload) returns a valid digest under an empty key and no empty-key precondition exists in the HMAC algorithm. The same path is reached when a keyfinder block or key_finder: argument returns an empty string, nil, or an array containing nil for an unknown key, affecting HS256, HS384, and HS512 verification through JWT.decode and JWT::EncodedToken#verify_signature!. This issue is fixed in versions 2.10.3 and 3.2.0.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-1391",
"CWE-287",
"CWE-326"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45363.json"
}{
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "2.10.3"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"introduced": "3.0.0"
},
{
"fixed": "3.2.0"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"fixed": "9820020869ad147b941e49d96ab8beba35532964"
}
],
"source": "REFERENCES_COMMIT"
},
{
"range": [
{
"fixed": "db560b769a07bd9724e77ff505011ac01872106f"
}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "v2.10.3",
"range": [
{
"fixed": "a52e81d2c6b6aa6ff4be929dfa69da6b52db2888"
}
],
"source": "REFERENCES_TAG"
},
{
"original_tag": "v3.2.0",
"range": [
{
"fixed": "db560b769a07bd9724e77ff505011ac01872106f"
}
],
"source": "REFERENCES_TAG"
}
]
}