Improper Authentication
js-stellar-sdk is a Javascript library for communicating with a Stellar Horizon server. The Utils.readChallengeTx function used in SEP-10 Stellar Web Authentication states in its function documentation that it reads and validates the challenge transaction including verifying that the serverAccountID has signed the transaction. In js-stellar-sdk, the function does not verify that the server has signed the transaction. Applications that also used Utils.verifyChallengeTxThreshold or Utils.verifyChallengeTxSigners to verify the signatures including the …