Server-side Request Forgery (SSRF) Affecting authlib package, versions [1.6.0,1.9.0)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-PYTHON-AUTHLIB-21460696
- published23 Oct 2026
- disclosed23 Oct 2026
- creditPriyank N
Introduced: 23 Oct 2026
NewCVE-2026-114620 (opens in a new tab)How to fix?
Upgrade authlib to version 1.9.0 or higher.
Overview
authlib is a library in building OAuth and OpenID Connect servers.
Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) via the parse_id_token function in sync_openid.py and async_openid.py, where an ID Token containing a nonce_supported: false claim causes nonce validation to be silently skipped. An attacker who can supply or replay an ID Token with this claim set can bypass nonce validation, enabling replay attacks against OpenID Connect authentication flows. Additionally, JWT Authorization Request (JAR) handling in authorization_server.py fails to validate request_uri values against registered URIs before retrieval, and does not enforce signature requirements independently of algorithm customization, allowing an attacker to supply an unregistered or attacker-controlled request_uri or an unsigned request object.