Contact Form by Supsystic <= 1.7.36 — Unauthenticated Server-Side Template Injection via Prefill Functionality
CVE-2026-4257Published · Updated Action summary
Affected: ≤1.7.36Update to 1.8.0 or newer
All remediation steps- Severity
- Critical9.8
- CVSS
- 9.8CVSS 3.1 · CNA (Wordfence)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HWhat does this vector mean?
AV:NAttack vector- Network
AC:LAttack complexity- Low
PR:NPrivileges required- None
UI:NUser interaction- None
S:UScope- Unchanged
C:HConfidentiality- High
I:HIntegrity- High
A:HAvailability- High
- Required access
- No account needed
- Exploit prediction (EPSS)
- No score
- CISA KEV
- Not listed
On this page8
Am I affected?
Contact Form by Supsystic – Drag & Drop Form Builder with Templates & Form Statistics contact-form-by-supsystic
- Affected≤ 1.7.36
- Patched in1.8.0
Update to 1.8.0 or newer.
You are affected if you run ≤ 1.7.36. Version 1.8.0 and later are not affected by this issue.
- Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Contact Form by Supsystic – Drag & Drop Form Builder with Templates & Form Statistics.
- No admin access? Run a passive check of your site. It reads public files only.
- No account is needed to exploit this. Treat any exposed site on an affected version as at risk.
What to do
- Update to version 1.8.0, or a newer patched version
- Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
- Watch Contact Form by Supsystic – Drag & Drop Form Builder with Templates & Form Statistics to get an email when the next vulnerability is published.
Advisory
Source description from Wordfence Intelligence, credited to Azril Fathoni (kiseki).
The Contact Form by Supsystic plugin for WordPress is vulnerable to Server-Side Template Injection (SSTI) leading to Remote Code Execution (RCE) in all versions up to, and including, 1.7.36. This is due to the plugin using the Twig `Twig_Loader_String` template engine without sandboxing, combined with the `cfsPreFill` prefill functionality that allows unauthenticated users to inject arbitrary Twig expressions into form field values via GET parameters. This makes it possible for unauthenticated attackers to execute arbitrary PHP functions and OS commands on the server by leveraging Twig's `registerUndefinedFilterCallback()` method to register arbitrary PHP callbacks.
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 Contact Form by Supsystic – Drag & Drop Form Builder with Templates & Form Statistics
All 21| Severity | Vulnerability | CVE | Published |
|---|---|---|---|
| Medium5.3 | Unauthenticated Information Exposure ≤1.10.5Update to 1.10.7 | CVE-2026-115591 | |
| Medium5.3 | Missing Authorization ≤1.10.7Update to 1.11.1 | CVE-2026-115595 | |
| High7.2 | Authenticated (Administrator+) Remote Code Execution ≤1.11.0Update to 1.11.1 | CVE-2026-115301 | |
| Medium5.3 | Missing Authorization ≤1.11.0Update to 1.11.1 | CVE-2026-115302 | |
| Medium4.3 | Cross-Site Request Forgery ≤1.11.0Update to 1.11.1 | CVE-2026-115300 |
- Medium5.3Unauthenticated Information Exposure
≤1.10.5Update to 1.10.7
- Medium5.3Missing Authorization
≤1.10.7Update to 1.11.1
- High7.2Authenticated (Administrator+) Remote Code Execution
≤1.11.0Update to 1.11.1
- Medium5.3Missing Authorization
≤1.11.0Update to 1.11.1
- Medium4.3Cross-Site Request Forgery
≤1.11.0Update to 1.11.1
Timeline
CVE published
Severity critical, CVSS 9.8
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.