PYSEC-2026-1814 PyJWT Issuer field partial matches allowed

Summary The wrong string if check is run for iss checking, resulting in "acb" being accepted for "abc". Details This is a bug introduced in version 2.10.0: checking the "iss" claim changed from isinstanceissuer, list to isinstanceissuer, Sequence. diff - if isinstanceissuer, list: + if...