Contact Form by Supsystic <= 1.7.36 - Unauthenticated Server-Side Template Injection via Prefill Functionality

MITRE NVD CVE.ORG Print: PDF PDF

Summary

CVECVE-2026-4257
StatePUBLISHED
AssignerWordfence
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-03-30 22:16:20 UTC
Updated2026-04-01 14:24:02 UTC
DescriptionThe 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.

Risk And Classification

Primary CVSS: v3.1 9.8 CRITICAL from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.127800000 probability, percentile 0.939750000 (date 2026-04-01)

Problem Types: CWE-94 | CWE-94 CWE-94 Improper Control of Generation of Code ('Code Injection')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

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

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Supsysticcom Contact Form By Supsystic affected * 1.7.36 semver Not specified

References

ReferenceSourceLinkTags
www.wordfence.com/threat-intel/vulnerabilities/id/415c9658-bfb2-453b-a697-c63c0... [email protected] www.wordfence.com
plugins.trac.wordpress.org/browser/contact-form-by-supsystic/tags/1.7.36/modules/forms/v... [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/changeset/3491826/contact-form-by-supsystic [email protected] plugins.trac.wordpress.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Azril Fathoni (en)

Additional Advisory Data

SourceTimeEvent
CNA2026-03-16T09:47:14.000ZVendor Notified
CNA2026-03-30T09:13:47.000ZDisclosed
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