CVE-2026-114616
High
Description
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to 1.9.1, Authlib's OctKey.import_key() and HMAC signing and verification path accept zero-length key material. If an application's secret lookup can return an empty string or empty bytes, a remote attacker can compute the deterministic HS256, HS384, or HS512 signature for arbitrary token claims and have Authlib treat the token as authentic. This issue is fixed in version 1.9.1.
SeverityHigh
CVSS7.4
Exploit probability—
ProductAuthlib
PublishedOct 22, 2026
First seenOct 22, 2026
How to fix
Update
- authlib1.9.1 or later
- authlib authlib1.9.1 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| authlibPyPI | v < 1.9.1 | 1.9.1 |
| authlib authlib | v < 1.9.1 | 1.9.1 |
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