CVE-2026-87070 in Forminator Forms Plugin
Summary
by MITRE • 09/23/2026
The Forminator Forms WordPress plugin before 1.57.2.1 does not verify that a request came from a trusted proxy before preferring client-supplied forwarding headers over the connecting address, and it uses that value both to enforce its per-visitor voting limit and to record who submitted an entry. Unauthenticated visitors can therefore vote without limit on any poll and can choose the address stored against every submission they make.
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Analysis
by VulDB Data Team • 09/23/2026
The vulnerability identified in Forminator Forms WordPress plugin versions prior to 1.57.2.1 represents a critical failure in input validation regarding network identity, specifically concerning how the application handles HTTP forwarding headers from reverse proxies or load balancers. In modern web architectures, it is common for requests to pass through intermediate infrastructure that modifies header fields such as X-Forwarded-For or CF-Connecting-IP to reflect the original client's IP address rather than the proxy's internal address. The flaw lies in the application's logic which blindly trusts these headers without verifying whether they originated from a trusted, authorized proxy server. This lack of validation allows an attacker to manipulate their perceived network identity by injecting arbitrary values into these header fields during HTTP requests directed at the vulnerable endpoint.
This technical deficiency has two significant operational impacts related to access control and data integrity. First, the plugin utilizes the client-supplied IP address to enforce per-visitor voting limits on polls. By spoofing different IP addresses through crafted headers, an unauthenticated visitor can bypass these restrictions entirely, allowing them to cast unlimited votes for any option in a poll. This undermines the fundamental purpose of polling mechanisms which rely on one-person-one-vote integrity, potentially leading to skewed results and manipulation of outcomes based on malicious intent rather than genuine user preference.
Secondly, the vulnerability affects data recording accuracy by allowing attackers to dictate the IP address stored against every submission they make. When a form entry is created, the application records the source IP as provided in the forwarded headers without verification. This means that an attacker can fabricate logs and audit trails, making it appear as though submissions originated from legitimate or specific target addresses rather than their actual location. This capability complicates forensic analysis and incident response efforts, as security teams cannot rely on the recorded IP data to trace malicious activity back to its true source.
From a classification perspective, this issue aligns with CWE-287 Improper Authentication, specifically regarding the failure to verify identity claims provided by external sources. It also relates closely to CWE-915 Improper Modification of Objects with Incorrectly Controlled Behavior Sequences, as the application modifies internal state based on untrusted input. In terms of attack vectors, this falls under ATT&CK technique T1078 Valid Accounts if combined with other exploits, but more accurately maps to data manipulation techniques where an adversary alters system information to evade detection or manipulate outcomes. The core issue is a lack of trust boundary enforcement between the application and its upstream infrastructure.
To mitigate this vulnerability, administrators must upgrade the Forminator Forms plugin to version 1.57.2.1 or later, which addresses these validation gaps by implementing proper checks for trusted proxy sources before accepting forwarded headers. For environments where immediate patching is not feasible, a temporary mitigation involves configuring web servers such as Nginx or Apache to strip untrusted X-Forwarded-For and similar headers from incoming requests that do not originate from known internal IP ranges. Additionally, deploying Web Application Firewalls with rules designed to detect header injection attempts can provide an additional layer of defense against this specific class of identity spoofing attacks.