Vulnerability · Published Jun 22, 2026 · Assigned by GitHub_M
CVE-2026-41479Authlib OAuth 2.0 authorization endpoint open redirects to attacker-controlled redirect_uri on unsupported response_type
Medium 5.4
In plain English
A medium-severity open redirect in authlib from authlib. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:13 | python-authlib | no fix listed | DEBIAN-CVE-2026-41479 |
| Debian:14 | python-authlib | 1.7.2-1 | DEBIAN-CVE-2026-41479 |
| PyPI | authlib | 1.7.1 | GHSA-w8p2-r796-3vmq |
| PyPI | authlib | 1.6.10 | PYSEC-2026-2119 |
| PyPI | authlib | 1.6.10 | GHSA-w8p2-r796-3vmq |
| Ubuntu:25.10 | python-authlib | no fix listed | UBUNTU-CVE-2026-41479 |
| Ubuntu:26.10 | python-authlib | no fix listed | UBUNTU-CVE-2026-41479 |
Affected products (as reported)
Weakness: CWE-601 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N