Summary

Unclear documentation of the error behavior in ParseWithClaims can lead to situation where users are potentially not checking errors in the way they should be. Especially, if a token is both expired and invalid, the errors returned by ParseWithClaims return both error codes. If users only check for the jwt.ErrTokenExpired using error.Is, they will ignore the embedded jwt.ErrTokenSignatureInvalid and thus potentially accept invalid tokens.

Fix

We have back-ported the error handling logic from the v5 branch to the v4 branch. In this logic, the ParseWithClaims function will immediately return in "dangerous" situations (e.g., an invalid signature), limiting the combined errors only to situations where the signature is valid, but further validation failed (e.g., if the signature is valid, but is expired AND has the wrong audience). This fix is part of the 4.5.1 release.

Workaround

We are aware that this changes the behaviour of an established function and is not 100 % backwards compatible, so updating to 4.5.1 might break your code. In case you cannot update to 4.5.0, please make sure that you are properly checking for all errors ("dangerous" ones first), so that you are not running in the case detailed above.

Go token, err := / jwt.Parse or similar / if token.Valid { fmt.Println("You look nice today") } else if errors.Is(err, jwt.ErrTokenMalformed) { fmt.Println("That's not even a token") } else if errors.Is(err, jwt.ErrTokenUnverifiable) { fmt.Println("We could not verify this token") } else if errors.Is(err, jwt.ErrTokenSignatureInvalid) { fmt.Println("This token has an invalid signature") } else if errors.Is(err, jwt.ErrTokenExpired) || errors.Is(err, jwt.ErrTokenNotValidYet) { // Token is either expired or not active yet fmt.Println("Timing is everything") } else { fmt.Println("Couldn't handle this token:", err) }

Insecure defaults in open-source Temporal Server before version 1.20 on all platforms allows an attacker to craft a task token with access to a namespace other than the one specified in the request. Creation of this task token must be done outside of the normal Temporal server flow. It requires the namespace UUID and information from the workflow history for the target namespace. Under these conditions, it is possible to interfere with pending tasks in other namespaces, such as marking a task failed or completed. If a task is targeted for completion by the attacker, the targeted namespace must also be using the same data converter configuration as the initial, valid, namespace for the task completion payload to be decoded by workers in the target namespace.