CVE-2026-28802
Authlib: Setting `alg: none` and a blank signature appears to bypass signature verification
CVSS Score
0.0
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-347 |
| Vendor | authlib |
| Product | authlib |
| Published | Mar 6, 2026 |
| Last Updated | Mar 6, 2026 |
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Affected Versions
authlib / authlib
>= 1.6.5, < 1.6.7