Versions `<=8.5.1` of `jsonwebtoken` library could be misconfigured so that legacy, insecure key types are used for signature verification. For example, DSA keys could be used with the RS256 algorithm. You are affected if you are using an algorithm and a key type other than a combination listed in the GitHub Security Advisory as unaffected. This issue has been fixed, please update to version 9.0.0. This version validates for asymmetric key type and algorithm combinations. Please refer to the above mentioned algorithm / key type combinations for the valid secure configuration. After updating to version 9.0.0, if you still intend to continue with signing or verifying tokens using invalid key type/algorithm value combinations, you’ll need to set the `allowInvalidAsymmetricKeyTypes` option to `true` in the `sign()` and/or `verify()` functions.

Versions `<=8.5.1` of `jsonwebtoken` library could be misconfigured so that legacy, insecure key types are used for signature verification. For example, DSA keys could be used with the RS256 algorithm. You are affected if you are using an algorithm and a key type other than a combination listed in the GitHub Security Advisory as unaffected. This issue has been fixed, please update to version 9.0.0. This version validates for asymmetric key type and algorithm combinations. Please refer to the above mentioned algorithm / key type combinations for the valid secure configuration. After updating to version 9.0.0, if you still intend to continue with signing or verifying tokens using invalid key type/algorithm value combinations, you’ll need to set the `allowInvalidAsymmetricKeyTypes` option to `true` in the `sign()` and/or `verify()` functions.

jsonwebtoken unrestricted key type could lead to legacy keys usage