CVE-2026-4257: Contact Form by Supsystic (WordPress plugin) · Code Injection
Affects Contact Form by Supsystic (WordPress plugin)Source CVE Database V5
Public exploit available (Metasploit, Exploit-DB) · 41% EPSS · CVSS 9.8 Critical.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 41.4% chance of exploitation in 30 days – higher than 98% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
t = 0 is the CVE’s publication on cve.org
Disclosed: evidence found.
CVE published 30 Mar 2026
Detectable: evidence found.
nuclei template: WordPress Contact Form by Supsystic - Server-Side Template Injection
Weaponized: evidence found.
1 Metasploit module · 1 Exploit-DB entry, 45 days after disclosure
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
Timeline
CVE ID reserved
by Wordfence
, 14 days before disclosure
CVE published
on cve.org
, t = 0
In Threat Radar
record ingested
, 27 minutes after disclosure
First Exploit-DB entry (opens in a new tab)
WordPress Plugin Supsystic Contact Form 1.7.36 - SSTI
, 45 days after disclosure
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| supsysticcomContact Form by Supsystic | Affected
| Fixed in– |
AI-suggested
Until an official fix is available, it is recommended to disable or remove the Contact Form by Supsystic plugin if possible. Restricting access to the vulnerable functionality or applying web application firewall rules to block malicious GET parameters may provide temporary mitigation. Monitor vendor channels for updates and apply patches promptly once released.
Description
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.
References
- wordfence.com/threat-intel/vulnerabilities/id/415c9658-bfb2-453b-a697-c63c08b0ca61?source=cve (opens in a new tab)
- plugins.trac.wordpress.org/browser/contact-form-by-supsystic/tags/1.7.36/modules/forms/views/forms.php (opens in a new tab)
- plugins.trac.wordpress.org/changeset/3491826/contact-form-by-supsystic (opens in a new tab)