CVE-2026-4257

criticalpriority · track · 25EPSS 0.415 · 99 %ileexploit · weaponizedEU

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

5 exploits · weaponized

Likely / severe?

41.5% (99th) EPSS

CVSS 9.8 · critical

Is it mine?

1 products

Check your exposure

Who says so?

2 sources

cnnvd · enisa_euvd

EPSS · scored 2026-10-28

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.

cvss

Technical severity, 0–10. One row per scoring source.

9.8

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · ENISA EU

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · security@wordfence.comexploitability 3.9 · impact 5.9

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Hsecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-94US

exploits (5)

Public proof-of-concept and weaponised exploit code.

exploit/multi/http/wp_plugin_supsystic_contact_form_rceSupsystic Contact Form Wordpress Plugin SSTI RCEweaponized · metasploit
EDB-52564WordPress Plugin Supsystic Contact Form 1.7.36 - SSTIPoC · exploit_db
bootstrapbool/cve-2026-4257bootstrapbool/cve-2026-4257PoC · poc_in_github
dann3xplo1t/CVE-2026-4257CVE-2026-4257 - Contact Form by Supsystic <= 1.7.36 # SSTI to RCE PoC · poc_in_github
shootcannon/CVE-2026-4257SSTI contact form to rcePoC · poc_in_github

affected products (1)

Products and version ranges known to be affected.

supsysticcom Contact Form by Supsystic≤ 0 ≤1.7.36enisa_euvdEU

also known as (2)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd NVD CVE.org MITRE

published 2026-03-30modified 2026-06-17

references (12)

External citations — patches, advisories, analysis.

scry

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