Craft CMS Vulnerable to Authenticated RCE via Twig SSTI - create() function + Symfony Process gadget
There is an authenticated admin RCE in Craft CMS 5.8.21 via Server-Side Template Injection using the create() Twig function combined with a Symfony Process gadget chain.
This bypasses the fix implemented for CVE-2025-57811 (patched in 5.8.7).
Required Permissions
- Administrator permissions or access to System Messages utility
allowAdminChangesenabled in production (against our security recommendations) or access to System Messages utility
Vulnerability Details
The create() Twig function exposes Craft::createObject(), which allows instantiation of arbitrary PHP classes with constructor arguments. Combined with the bundled symfony/process dependency, this enables RCE.
Attack Vector
Admin panel → Settings → Entry Types → Title Format field
Proof of Concept Payload
{% set p = create("Symfony\\Component\\Process\\Process", [["id"]])
%}{{ p.mustRun.getOutput }}
Steps to Reproduce
- Log in as admin
- Navigate to Settings → Entry Types
- Edit any entry type’s "Title Format" field
- Insert the payload above
- Create/edit an entry of that type
- Command executes, output appears in entry title
Impact
- Authenticated Remote Code Execution
- Runs as web server user (root in default Docker setup)
- Full server compromise
Root Cause
Craft::createObject() allows the instantiation of any class, including
Symfony\Component\Process\Process, which executes shell commands.
Suggested Fix
- Blocklist dangerous classes in createObject() when called from Twig
- Or remove/restrict the create() Twig function
- Or validate class names against an allowlist
Resources
https://github.com/craftcms/cms/commit/e31e50849ad71638e11ea55fbd1ed90ae8f8f6e0
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | craftcms/cms | >= 5.8.7, < 5.9.0-beta.1, >= 4.0.0-RC1, < 4.17.0-beta.1 | 5.9.0-beta.1, 4.17.0-beta.1 |
References
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P- Weakness (CWE)
CWE-1336, CWE-22, CWE-94- Platform
- Composer
- Package
craftcms/cms- Disclosed
- 03.03.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-94rc-cqvm-m4pw - CC BY 4.0
Vulnerability history: craftcms/cms
All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 127
- First → latest
- 07.2021 08.2026
- Without a fix
- 6
- Exploited in attacks
- 4
Severity breakdown
- Critical 9
- High 41
- Medium 65
- Low 12
Disclosures per year
- 2021: 3
- 2022: 22
- 2023: 13
- 2024: 9
- 2025: 6
- 2026: 74
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