python-jwt is a module for generating and verifying JSON Web Tokens. Versions prior to 3.3.4 are subject to Authentication Bypass by Spoofing, resulting in identity spoofing, session hijacking or authentication bypass. An attacker who obtains a JWT can arbitrarily forge its contents without knowing the secret key. Depending on the application, this may for example enable the attacker to spoof other user's identities, hijack their sessions, or bypass authentication. Users should upgrade to version 3.3.4. There are no known workarounds.

PyJWT is a Python implementation of RFC 7519. PyJWT supports multiple different JWT signing algorithms. With JWT, an attacker submitting the JWT token can choose the used signing algorithm. The PyJWT library requires that the application chooses what algorithms are supported. The application can specify `jwt.algorithms.get_default_algorithms()` to get support for all algorithms, or specify a single algorithm. The issue is not that big as `algorithms=jwt.algorithms.get_default_algorithms()` has to be used. Users should upgrade to v2.4.0 to receive a patch for this issue. As a workaround, always be explicit with the algorithms that are accepted and expected when decoding.

The Simple JWT Login WordPress plugin before 3.3.0 can be used to create new WordPress user accounts with a randomly generated password. The password is generated using the str_shuffle PHP function that "does not generate cryptographically secure values, and should not be used for cryptographic purposes" according to PHP's documentation.

The Simple JWT Login WordPress plugin before 3.2.1 does not have nonce checks when saving its settings, allowing attackers to make a logged in admin changed them. Settings such as HMAC verification secret, account registering and default user roles can be updated, which could result in site takeover.

JWT is a library to work with JSON Web Token and JSON Web Signature. Prior to versions 3.4.6, 4.0.4, and 4.1.5, users of HMAC-based algorithms (HS256, HS384, and HS512) combined with `Lcobucci\JWT\Signer\Key\LocalFileReference` as key are having their tokens issued/validated using the file path as hashing key - instead of the contents. The HMAC hashing functions take any string as input and, since users can issue and validate tokens, users are lead to believe that everything works properly. Versions 3.4.6, 4.0.4, and 4.1.5 have been patched to always load the file contents, deprecated the `Lcobucci\JWT\Signer\Key\LocalFileReference`, and suggest `Lcobucci\JWT\Signer\Key\InMemory` as the alternative. As a workaround, use `Lcobucci\JWT\Signer\Key\InMemory` instead of `Lcobucci\JWT\Signer\Key\LocalFileReference` to create the instances of one's keys.

jwt-go before 4.0.0-preview1 allows attackers to bypass intended access restrictions in situations with []string{} for m["aud"] (which is allowed by the specification). Because the type assertion fails, "" is the value of aud. This is a security problem if the JWT token is presented to a service that lacks its own audience check.

The json-jwt gem before 1.11.0 for Ruby lacks an element count during the splitting of a JWE string.

perl-CRYPT-JWT 0.022 and earlier is affected by: Incorrect Access Control. The impact is: bypass authentication. The component is: JWT.pm for JWT security token, line 614 in _decode_jws(). The attack vector is: network connectivity(crafting user-controlled input to bypass authentication). The fixed version is: 0.023.

Perl Crypt::JWT prior to 0.023 is affected by: Incorrect Access Control. The impact is: allow attackers to bypass authentication by providing a token by crafting with hmac(). The component is: JWT.pm, line 614. The attack vector is: network connectivity. The fixed version is: after commit b98a59b42ded9f9e51b2560410106207c2152d6c.

Nov json-jwt version >= 0.5.0 && < 1.9.4 contains a CWE-347: Improper Verification of Cryptographic Signature vulnerability in Decryption of AES-GCM encrypted JSON Web Tokens that can result in Attacker can forge a authentication tag. This attack appear to be exploitable via network connectivity. This vulnerability appears to have been fixed in 1.9.4 and later.