CVE-2026-28802
Critical
Description
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.
SeverityCritical
CVSS9.8
Exploit probability—
ProductAuthlib
PublishedMar 6, 2026
First seenMar 6, 2026
Weakness typeCWE-347CWE-347
How to fix
Update
- authlib authlib1.6.7 or later
- authlib1.6.7 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| authlib authlib | 1.6.5 ≤ v < 1.6.7 | 1.6.7 |
| authlibPyPI | 1.6.5 ≤ v < 1.6.7 | 1.6.7 |
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