- Release Date: January 28, 2025
- Component Type: Third party extension. This extension is not a part of the TYPO3 default installation.
- Component: "OpenID Connect Authentication" (oidc)
- Composer Package Name: causal/oidc
- Vulnerability Type: Account Takeover
- Affected Versions: 3.0.0 and below
- Severity: Low
- Suggested CVSS v3.1: AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N/E:F/RL:O/RC:C
- References: CVE-2025-24856, CWE-639, CWE-288
Problem Description
A vulnerability in the account linking logic of the extension allows a pre-hijacking attack leading to Account Takeover. The attack can only be exploited if the following requirements are met:
- An attacker can anticipate the email address of the user.
- An attacker can register a public frontend user account using that email address before the user's first OIDC login.
- The IDP returns the field email containing the email address of the user
Solution
An updated versions 4.0.0 is available from the TYPO3 extension manager, packagist and at
https://extensions.typo3.org/extension/download/oidc/4.0.0/zip
Users of the extension are advised to update the extension as soon as possible.
Important: The fixed version contains a breaking change, because the “username” field has been removed from the OIDC authentication service user lookup. Users relying on this functionality can use the AuthenticationFetchUserEvent to adjust the lookup criteria, but must ensure that the lookup criteria does not include a field name with user-generated content.
Credits
Thanks to Hannes Lau for reporting the issue and to Markus Klein for providing an updated version of the extension.
General Advice
Follow the recommendations that are given in the TYPO3 Security Guide. Please subscribe to the typo3-announce mailing list.