Contact Form Plugin by Fluent Forms for Quiz, Survey, and Drag & Drop WP Form Builder <= 5.1.15 — PHP Object Injection via extractDynamicValues
CVE-2024-4157Published · Updated Action summary
Affected: ≤5.1.15Update to 5.1.16 or newer
All remediation steps- Severity
- High7.5
- CVSS
- 7.5CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HWhat does this vector mean?
AV:NAttack vector- Network
AC:HAttack complexity- High
PR:LPrivileges required- Low
UI:NUser interaction- None
S:UScope- Unchanged
C:HConfidentiality- High
I:HIntegrity- High
A:HAvailability- High
- Weakness
- CWE-502 PHP Object Injection
- Required access
- Unknown
- Exploit prediction (EPSS)
- No score
- CISA KEV
- Not listed
On this page8
Am I affected?
Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder fluentform
- Affected≤ 5.1.15
- Patched in5.1.16
Update to 5.1.16 or newer.
You are affected if you run ≤ 5.1.15. Version 5.1.16 and later are not affected by this issue.
- Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder.
- No admin access? Run a passive check of your site. It reads public files only.
What to do
- Update to version 5.1.16, or a newer patched version
- Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
- Watch Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder to get an email when the next vulnerability is published.
Advisory
Source description from Wordfence Intelligence, credited to Tobias Weißhaar (kun_19).
The Contact Form Plugin by Fluent Forms for Quiz, Survey, and Drag & Drop WP Form Builder plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 5.1.15 via deserialization of untrusted input in the extractDynamicValues function. This makes it possible for authenticated attackers, with contributor-level access and above, to inject a PHP Object. If a POP chain is present via an additional plugin or theme installed on the target system, it could allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code. Successful exploitation requires the attacker to have "View Form" and "Manage Form" permissions, which must be explicitly set by an administrator. However, this requirement can be bypassed when this vulnerability is chained with CVE-2024-2771.
Exploits & references
Proof-of-concept & detection
No public proof-of-concept or detection template is known for this vulnerability.
Advisories & patches
- Advisorywordfence.com
Related CVEs
More in Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder
All 47| Severity | Vulnerability | CVE | Published |
|---|---|---|---|
| Medium5.3 | Missing Authorization ≤6.2.16Update to 6.2.17 | CVE-2026-120858 | |
| Medium5.3 | Missing Authorization ≤6.2.15Update to 6.2.16 | CVE-2026-111831 | |
| Medium5.4 | Missing Authorization to Authenticated (Custom+) Sensitive Data Exposure and Modification ≤6.2.5Update to 6.2.6 | CVE-2026-15178 | |
| Medium4.7 | Reflected Cross-Site Scripting via '{get.*}' Editor SmartCode Parameter ≤6.2.14Update to 6.2.15 | CVE-2026-101324 | |
| Medium6.4 | Authenticated (Contributor+) Stored Cross-Site Scripting ≤6.2.14Update to 6.2.15 | CVE-2026-103343 |
- Medium5.3Missing Authorization
≤6.2.16Update to 6.2.17
- Medium5.3Missing Authorization
≤6.2.15Update to 6.2.16
- Medium5.4Missing Authorization to Authenticated (Custom+) Sensitive Data Exposure and Modification
≤6.2.5Update to 6.2.6
- Medium4.7Reflected Cross-Site Scripting via '{get.*}' Editor SmartCode Parameter
≤6.2.14Update to 6.2.15
- Medium6.4Authenticated (Contributor+) Stored Cross-Site Scripting
≤6.2.14Update to 6.2.15
Same weakness (PHP Object Injection)
All PHP Object Injection| Severity | Vulnerability | CVE | Published |
|---|---|---|---|
| High7.2 | Unauthenticated Stored Cross-Site Scripting via Comment User-Agent Header | CVE-2026-120688 | |
| Critical9.8 | Unauthenticated Arbitrary File Upload via File Upload via Public Form Submission | CVE-2026-125055 | |
| Critical9.8 | Unauthenticated PHP Object Injection to Remote Code Execution via 'form' Parameter | CVE-2026-119077 | |
| Medium5.3 | Unauthenticated Sensitive Information Exposure in 'search' Parameter | CVE-2026-121518 |
- High7.2Unauthenticated Stored Cross-Site Scripting via Comment User-Agent Header
EZ SQL Reports Shortcode Widget and DB Backup
≤5.25.25Update to 5.26.45
- Critical9.8Unauthenticated Arbitrary File Upload via File Upload via Public Form Submission
Chatterbug Forms – Fast, Flexible WordPress Form Builder
≤1.0.2Update to 1.1
- Critical9.8Unauthenticated PHP Object Injection to Remote Code Execution via 'form' Parameter
ELEX WordPress HelpDesk & Customer Ticketing System
≤3.3.9Update to 3.4.0
- Medium5.3Unauthenticated Sensitive Information Exposure in 'search' Parameter
Customer Reviews for WooCommerce
≤5.127.0Update to 5.128.0
Timeline
CVE published
Severity high, CVSS 7.5
Record last updated
Sources & licenses
Wordfence record- Vulnerability data
- Wordfence Intelligence. Copyright 2012-2026 Defiant Inc. Licensed under the CC BY-SA 4.0.
- CVE® identifiers
- Copyright 1999-2026 The MITRE Corporation. Used under the CVE Program. CVE® is a registered trademark of The MITRE Corporation.
- CVSS / CWE
- National Vulnerability Database (NVD), shown unmodified. This product uses the NVD API but is not endorsed or certified by the NVD.
- VulnCrest content
- Summary, remediation guidance and page layout © VulnCrest. Not sourced from NVD.