Craft is a content management system (CMS). Prior to 4.17.0-beta.1 and 5.9.0-beta.1, an authenticated administrator can achieve Remote Code Execution (RCE) by injecting a Server-Side Template Injection (SSTI) payload into Twig template fields (e.g., Email Templates). By calling the craft.app.fs.write() method, an attacker can write a malicious PHP script to a web-accessible directory and subsequently access it via the browser to execute arbitrary system commands. This vulnerability is fixed in 4.17.0-beta.1 and 5.9.0-beta.1.
https://github.com/craftcms/cms/security/advisories/GHSA-v47q-jxvr-p68x
https://github.com/craftcms/cms/pull/18219
https://github.com/craftcms/cms/pull/18216
https://github.com/craftcms/cms/commit/9dc2a4a3ec8e9cd5e8c0d1129f36371437519197
Published: 2026-03-04
Updated: 2026-03-05
Base Score: 8.3
Vector: CVSS2#AV:N/AC:L/Au:M/C:C/I:C/A:C
Severity: High
Base Score: 9.1
Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Severity: Critical
Base Score: 9.4
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Severity: Critical
EPSS: 0.00283