Overview
The cybersecurity community is currently dealing with a newly discovered high risk vulnerability, known as CVE-2025-54336, that affects Plesk Obsidian 18.0.70. This vulnerability could potentially allow unauthorized access to systems, leading to data leakage or full system compromise. The threat is elevated due to the fact that Plesk is a widely used web hosting control panel software, so a high number of systems globally could be at risk. Securing this vulnerability should be treated as a priority for any organization using the affected version of Plesk.
Vulnerability Summary
CVE ID: CVE-2025-54336
Severity: Critical (9.8 CVSS)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
Plesk Obsidian | 18.0.70
How the Exploit Works
The vulnerability lies in the way Plesk Obsidian 18.0.70 validates admin passwords. Specifically, the function _isAdminPasswordValid uses an == comparison instead of a === comparison. If the correct password starts with “0e” followed by any digit string, an attacker can log in with any other string that evaluates to 0.0, such as “0e0”. This lack of strict type checking allows for a potential authentication bypass.
Conceptual Example Code
This is a conceptual example of how an attacker might exploit this vulnerability. They can attempt to login as an admin by passing “0e0” as the password in an HTTP POST request, like this:
POST /login HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
username=admin&password=0e0If the original admin password begins with “0e” followed by any digit string, this will cause the system to incorrectly validate the attacker’s login attempt as successful.
Mitigation
At present, the recommended mitigation guidance for CVE-2025-54336 is to apply the vendor-provided patch. If this is not immediately possible, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can offer temporary protection by monitoring and potentially blocking malicious traffic. All users of Plesk Obsidian 18.0.70 should look to apply these mitigations as promptly as possible to protect themselves from potential system compromise or data leakage.