CVE-2026-114614

Low

Description

Authlib is a Python library which builds OAuth and OpenID Connect servers. From 0.13 until 1.8.0, authlib.common.security.is_secure_transport() uses a textual prefix comparison for loopback HTTP exemptions, so a URL whose userinfo begins with a loopback host can be accepted even when its parsed host is an external non-loopback system. An external party able to supply a URL to OIDC RP-Initiated Logout registration, authorization-server metadata validation, or another call site can bypass the TLS-required guard and cause cleartext redirection or acceptance of cleartext endpoints. The issue does not bypass redirect URI exact matching and does not by itself forge tokens or authenticate users. The vulnerable authlib.common.security.is_secure_transport() implementation in authlib/common/security.py misinterprets the userinfo component before OIDC RP-Initiated Logout dynamic client registration and other consumers enforce transport security. This issue is fixed in version 1.8.0.

SeverityLow
CVSS2.6
Exploit probability—
ProductAuthlib
PublishedOct 22, 2026
First seenOct 22, 2026

How to fix

Update
  • authlib1.8.0 or later
  • authlib authlib1.8.0 or later

Affected products

ProductAffected versionsFixed in
authlibPyPIv < 1.8.01.8.0
authlib authlib0.13 ≤ v < 1.8.01.8.0

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