CVE-2026-28697CWE-1336

Craft Affected by Authenticated RCE via "craft.app.fs.write()" in Twig Templates

Critical · published March 4, 2026

CVSS v4.0
9.4
EPSS
1%
Percentile
66.9
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
9.4 · CRITICAL
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
EPSS
0.01162 · 66.9th percentile
Weakness
CWE-1336 · Improper Neutralization of Special Elements Used in a Template Engine
Published
2026-03-04T16:26Z
EPSS history
Timeline
  • 04 MAR 16:26Z
    Craft Affected by Authenticated RCE via "craft.app.fs.write()" in Twig Templates
    cvelistv5