CVE-2025-24856Network attack vector

Account takeover via email-based account linking

Published Mar 16, 2025 · Updated Mar 17, 2025

Account takeover in TYPO3 OpenID Connect Authentication before 4.0.0 allows remote attackers to seize a frontend user account. AuthenticationService.php matches the identity provider's email claim against the local username field instead of linking solely by the provider subject identifier. Exploitation requires advance knowledge of the victim's email address, prior registration of that address as a public frontend username, and the victim's first OIDC login through a provider that returns the email claim.

CVSS severity4.2
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Account takeover in TYPO3 OpenID Connect Authentication before 4.0.0 allows remote attackers to seize a frontend user account. AuthenticationService.php matches the identity provider's email claim against the local username field instead of linking solely by the provider subject identifier. Exploitation requires advance knowledge of the victim's email address, prior registration of that address as a public frontend username, and the victim's first OIDC login through a provider that returns the email claim.

The record

CVE
CVE-2025-24856
Published
Mar 16, 2025
Updated
Mar 17, 2025
Vendor
in2code GmbH
Product
OpenID Connect Authentication
Classifications
CWE-639, CWE-288, CWE-348, T1078
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Mar 17, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <4.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

in2code GmbH · OpenID Connect Authenticationversion=0 <4.0.0

Published CVSS scores

4.2GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-639Authorization Bypass Through User-Controlled Key
CWE-288Authentication Bypass Using an Alternate Path or Channel
CWE-348Use of Less Trusted Source
T1078Valid Accounts

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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