Open Redirect in Authlib
CVE-2026-41479
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to 1.6.10 and 1.7.1, Authlib's OAuth 2.0 authorization endpoint can be turned into an unauthenticated open redirect when a request uses an unsupported response_type and supplies an attacker-controlled redirect_uri. The vulnerable behavior happens before client lookup and before any redirect URI validation. As a result, an attacker does not need a valid client registration, an authenticated user, or any prior state. A single request to the authorization endpoint is enough to obtain a 302 Location response to an arbitrary attacker-controlled URL. This vulnerability is fixed in 1.6.10 and 1.7.1.
Vulnerability class: Open Redirect
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (15.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 16th percentile — 15.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Authlib — versions < 1.6.10, 1.7.0, = 1.7.0
Weakness classification (CWE)
References
- github.com/authlib/authlib/security/advisories/GHSA-w8p2-r796-3vmq (Exploit, Vendor Advisory)
- github.com/authlib/authlib/commit/3be08468201a7766a93012ce149ea12822cab096 (Patch)
Frequently asked questions
- What is CVE-2026-41479?
- CVE-2026-41479 is a medium-severity vulnerability in Authlib, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 5.4/10. Published 2026-06-22.
- How severe is CVE-2026-41479?
- Medium severity. CVSS v3 base score is 5.4 out of 10.