Overview
The CVE-2025-54391 is a severe vulnerability that specifically affects users of Zimbra Collaboration (ZCS), a popular open-source email platform. This vulnerability allows an attacker to bypass the Two-Factor Authentication (2FA) system, which is a commonly used security measure designed to add an extra layer of protection to user accounts. This vulnerability is particularly alarming because it enables potential unauthorized access to accounts that users believe to be securely protected by 2FA, raising the stakes for potential data leakage or system compromise.
Vulnerability Summary
CVE ID: CVE-2025-54391
Severity: Critical (CVSS: 9.1)
Attack Vector: Network
Privileges Required: User
User Interaction: Required
Impact: Unauthorized access to accounts, potential system compromise, and data leakage.
Affected Products
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Product | Affected Versions
Zimbra Collaboration | All versions prior to the patched release
How the Exploit Works
The exploit takes advantage of a vulnerability in the EnableTwoFactorAuthRequest SOAP endpoint of ZCS. An attacker with valid user credentials can exploit this vulnerability to configure an additional 2FA method, either through a third-party authenticator app or email-based 2FA, without presenting a valid authentication token or proving access to an already configured 2FA method. This bypasses the 2FA protection, allowing unauthorized access to the account.
Conceptual Example Code
Here’s a conceptual example of how the vulnerability might be exploited. This is a sample SOAP request to the vulnerable endpoint:
POST /service/soap/EnableTwoFactorAuthRequest HTTP/1.1
Host: target.example.com
Content-Type: text/xml; charset=utf-8
SOAPAction: "urn:zimbraAccount/EnableTwoFactorAuthRequest"
<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Body>
<EnableTwoFactorAuthRequest xmlns="urn:zimbraAccount">
<account by="name">target@example.com</account>
<authToken>...</authToken>
<method>...</method>
</EnableTwoFactorAuthRequest>
</soap:Body>
</soap:Envelope>In this example, the attacker would replace the ‘…’ placeholders with malicious payloads to enable an additional 2FA method without providing a valid authentication token.
Mitigation
Users are strongly advised to apply the vendor patch as soon as it becomes available. In the interim, a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can be used as a temporary mitigation to help protect against potential exploitation of this vulnerability. Please note that these are temporary measures, and the vendor patch should be applied as soon as possible for a complete resolution.