CVE-2025-24856: TYPO3 Oidc

Medium severity, CVSS 4.2. EPSS: 0.2% chance of exploitation in the next 30 days.

An issue was discovered in the oidc (aka OpenID Connect Authentication) extension before 4.0.0 for TYPO3. The account linking logic allows a pre-hijacking attack, leading to Account Takeover. The attack can only be exploited if the following requirements are met: (1) an attacker can anticipate the e-mail address of the user, (2) an attacker can register a public frontend user account using that e-mail address before the user's first OIDC login, and (3) the IDP returns an email field containing the e-mail address of the user,

Affected products

• TYPO3 Oidc: before 4.0.0 (fixed in 4.0.0)

Published 2025-03-16. Last modified 2026-06-17.