CVE-2026-104056
Received Received - Intake

Authlib Discovery Cache Poisoning Vulnerability

Publication date: 2026-10-01

Last updated on: 2026-10-01

Assigner: CERT/CC

Description
Authlib version 1.7.2 and below contains a vulnerability where discovery JSON metadata is cached without validation or issuer-origin binding. This allows a poisoned discovery response to replace all endpoint values with attacker-controlled values rather than endpoint URLs that share the origin of the configured server metadata URL.

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Meta Information

Published
2026-10-01
Last Modified
2026-10-01
Generated
2026-10-01
AI Q&A
2026-10-01
EPSS Evaluated
N/A
NVD
CVE-2026-104056
EUVD
EUVD-2026-91003

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
authlib authlib to 1.7.2 (inc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

Authlib versions 1.7.2 and below have a flaw where discovery JSON metadata is cached without proper validation or issuer-origin binding. This means an attacker could manipulate the discovery response to replace legitimate endpoint URLs with attacker-controlled values, even if those values do not share the same origin as the configured server metadata URL.

Impact Analysis

This vulnerability could allow attackers to redirect authentication flows to malicious endpoints, potentially leading to unauthorized access to user accounts or sensitive data. It undermines the security of OAuth/OpenID Connect implementations using affected Authlib versions.

Mitigation Strategies

Upgrade Authlib to a version higher than 1.7.2 where the discovery JSON metadata caching issue has been fixed. Review cached discovery responses for any unauthorized modifications and ensure issuer-origin binding is enforced in the configuration.

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