Everest Forms Pro Plugin up to 1.9.7 on WordPress mime_content_type deserialization

Summaryinfo

A vulnerability, which was classified as critical, has been found in Everest Forms Pro Plugin up to 1.9.7 on WordPress. Impacted is the function mime_content_type. This manipulation causes deserialization. This vulnerability is handled as CVE-2025-8871. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Everest Forms Pro Plugin up to 1.9.7 on WordPress. It has been declared as critical. Affected by this vulnerability is the function mime_content_type. The manipulation with an unknown input leads to a deserialization vulnerability. The CWE definition for the vulnerability is CWE-502. The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

The Everest Forms (Pro) plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 1.9.7 via deserialization of untrusted input in the mime_content_type() function. This makes it possible for unauthenticated attackers to inject a PHP Object. This vulnerability may be exploited by unauthenticated attackers when a form is present on the site with a non-required signature form field along with an image upload field. No known POP chain is present in the vulnerable software, which means this vulnerability has no impact unless another plugin or theme containing a POP chain is installed on the site. If a POP chain is present via an additional plugin or theme installed on the target system, it may allow the attacker to perform actions like delete arbitrary files, retrieve sensitive data, or execute code depending on the POP chain present. This vulnerability is only exploitable in PHP versions prior to 8.

It is possible to read the advisory at wordfence.com. This vulnerability is known as CVE-2025-8871. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 11/08/2025).

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 CNNVD (CNNVD-202511-467). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• WordPress Plugin

Name

• Everest Forms Pro Plugin

Version

• 1.9.0
• 1.9.1
• 1.9.2
• 1.9.3
• 1.9.4
• 1.9.5
• 1.9.6
• 1.9.7

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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