Critical · published March 6, 2026
Authlib is a Python library which builds OAuth and OpenID Connect servers. From version 1.6.5 to before version 1.6.7, previous tests involving passing a malicious JWT containing alg: none and an empty signature was passing the signature verification step without any changes to the application code when a failure was expected.. This issue has been patched in version 1.6.7.
| Product | Versions | Fixed in |
|---|---|---|
| authlib/authlib | ≥ 1.6.5, < 1.6.7 | 1.6.7 |