Nginx Cache Purge Preload Plugin up to 2.1.1 on WordPress nppp_preload_cache_on_update HTTP_REFERERER code injection

Summaryinfo

A vulnerability, which was classified as critical, was found in Nginx Cache Purge Preload Plugin up to 2.1.1 on WordPress. This issue affects the function nppp_preload_cache_on_update. Executing a manipulation of the argument HTTP_REFERERER can lead to privilege escalation. This vulnerability is registered as CVE-2025-6213. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability has been found in Nginx Cache Purge Preload Plugin up to 2.1.1 on WordPress and classified as critical. This vulnerability affects the function nppp_preload_cache_on_update. The manipulation of the argument HTTP_REFERERER with an unknown input leads to a privilege escalation vulnerability. The CWE definition for the vulnerability is CWE-94. The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

The Nginx Cache Purge Preload plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, 2.1.1 via the 'nppp_preload_cache_on_update' function. This is due to insufficient sanitization of the $_SERVER['HTTP_REFERERER'] parameter passed from the 'nppp_handle_fastcgi_cache_actions_admin_bar' function. This makes it possible for authenticated attackers, with Administrator-level access and above, to execute code on the server.

The advisory is shared for download at wordfence.com. This vulnerability was named CVE-2025-6213 since 06/17/2025. The exploitation appears to be easy. The attack can be initiated remotely. The exploitation requires an enhanced level of successful authentication. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 08/02/2025). The MITRE ATT&CK project declares the attack technique as T1059.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2025-22300). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Web Server

Name

• Nginx Cache Purge Preload Plugin

Version

• 2.1.0
• 2.1.1

License

• open-source

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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