{"id":"CVE-2026-120459","published":"2026-11-02T15:17:29.867","lastModified":"2026-11-02T19:14:53.030","description":"python-jose through 3.5.0 contains an authentication bypass vulnerability that allows unauthenticated attackers to forge JWTs because HMACKey and CryptographyHMACKey accept zero-length HMAC secrets. When an application's HS256/HS384/HS512 verification key resolves to empty, such as an oct JWK with empty k, attackers can forge tokens with arbitrary claims that jwt.decode accepts.","cvssScore":7.4,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","cwes":["CWE-347"],"vendors":[],"products":[],"references":[{"url":"https://github.com/mpdavis/python-jose/blob/3.5.0/jose/backends/cryptography_backend.py","tags":[]},{"url":"https://github.com/mpdavis/python-jose/blob/3.5.0/jose/backends/native.py","tags":[]},{"url":"https://github.com/mpdavis/python-jose/issues/398","tags":[]},{"url":"https://www.vulncheck.com/advisories/python-jose-through-3.5.0-authentication-bypass-via-empty-hmac-key","tags":[]}],"exploitRefs":[{"url":"https://github.com/mpdavis/python-jose/blob/3.5.0/jose/backends/cryptography_backend.py","tags":[]},{"url":"https://github.com/mpdavis/python-jose/blob/3.5.0/jose/backends/native.py","tags":[]},{"url":"https://github.com/mpdavis/python-jose/issues/398","tags":[]}],"hasPoc":true,"ai":null}