What is CVE-2026-116672?

CVE-2026-116672 is a high-severity vulnerability in Authlib, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 8.8/10. Published 2026-10-27.

How severe is CVE-2026-116672?

High severity. CVSS v3 base score is 8.8 out of 10.

RCE in Authlib

CVE-2026-116672

Authlib is a Python library which builds OAuth and OpenID Connect servers. From 0.15 until 1.9.1, the documented ClientConfigurationEndpoint.authenticate_client and ClientConfigurationEndpoint.check_permission reference implementations look up a target client from request-controlled client_id data and check only whether that target is editable, without verifying that request.credential belongs to the target client. Deployments following both examples can allow a client holding any valid registration access token to read, modify, or delete another client's registration. Changing redirect_uris can enable authorization code or token interception, while deleting registrations can deny service to affected clients. This issue is fixed in version 1.9.1.

Vulnerability class: IDOR (Insecure Direct Object Reference)

Published 2026-10-27 · last modified 2026-10-27.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Authlib — versions >= 0.15, < 1.9.1

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-116672?: CVE-2026-116672 is a high-severity vulnerability in Authlib, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 8.8/10. Published 2026-10-27.
How severe is CVE-2026-116672?: High severity. CVSS v3 base score is 8.8 out of 10.