Overview
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.
Am I affected?
You are affected if you are using an algorithm and a key type other than the combinations mentioned below
| Key type |
algorithm |
| ec |
ES256, ES384, ES512 |
| rsa |
RS256, RS384, RS512, PS256, PS384, PS512 |
| rsa-pss |
PS256, PS384, PS512 |
And for Elliptic Curve algorithms:
alg |
Curve |
| ES256 |
prime256v1 |
| ES384 |
secp384r1 |
| ES512 |
secp521r1 |
How do I fix it?
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.
Will the fix impact my users?
There will be no impact, if you update to version 9.0.0 and you already use a valid secure combination of key type and algorithm. Otherwise, use the allowInvalidAsymmetricKeyTypes option to true in the sign() and verify() functions to continue usage of invalid key type/algorithm combination in 9.0.0 for legacy compatibility.