Fluent Forms Plugin up to 5.1.16/6.1.0 on WordPress parseUserProperties deserialization

Summaryinfo

A vulnerability was found in Fluent Forms Plugin up to 5.1.16/6.1.0 on WordPress. It has been declared as critical. The affected element is the function parseUserProperties. Executing a manipulation can lead to deserialization. The identification of this vulnerability is CVE-2025-9260. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability classified as critical was found in Fluent Forms Plugin up to 5.1.16/6.1.0 on WordPress. This vulnerability affects the function parseUserProperties. 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. CVE summarizes:

The Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder plugin for WordPress is vulnerable to PHP Object Injection in versions 5.1.16 to 6.1.1 via deserialization of untrusted input in the parseUserProperties function. This makes it possible for authenticated attackers, with Subscriber-level access and above, to inject a PHP Object. The additional presence of a POP chain allows attackers to read arbitrary files. If allow_url_include is enabled on the server, remote code execution is possible. While the vendor patched this issue in version 6.1.0, the patch caused a fatal error in the vulnerable code, due to a missing class import, so we consider 6.1.2 to be the most complete and best patched version

The advisory is available at wordfence.com. This vulnerability was named CVE-2025-9260. The exploitation appears to be easy. The attack can be initiated remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 09/03/2025).

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

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Productinfo

Type

• WordPress Plugin

Name

• Fluent Forms Plugin

Version

• 5.1.0
• 5.1.1
• 5.1.2
• 5.1.3
• 5.1.4
• 5.1.5
• 5.1.6
• 5.1.7
• 5.1.8
• 5.1.9
• 5.1.10
• 5.1.11
• 5.1.12
• 5.1.13
• 5.1.14
• 5.1.15
• 5.1.16
• 6.0
• 6.1.0

CPE 2.3info

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• 🔒
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CPE 2.2info

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• 🔒
• 🔒

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Entryinfo

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