CVE-2026-72778 — Craft CMS versions from 4.0.0-RC1 before 4.18.2 and from 5.0.0-RC1 before 5.10.6 contain…¶

Key facts

CVE-2026-72778 is a High (8.8) vulnerability: Craft CMS versions from 4.0.0-RC1 before 4.18.2 and from 5.0.0-RC1 before 5.10.6 contain…. This entry ships a detection-only PoC and a Docker test lab.


CVE	CVE-2026-72778
Severity	High (8.8)
Detection / prevention	—
PoC	poc.py
Source	2026/CVE-2026-72778/

Details¶

English | 한국어

Description¶

Craft CMS versions from 4.0.0-RC1 before 4.18.2 and from 5.0.0-RC1 before 5.10.6 contain an authenticated remote code execution vulnerability in the control panel element-search condition handling. Craft cleanses the outer request-controlled condition array via Component::cleanseConfig(), but Conditions::createCondition() later decodes and merges the JSON string in condition.config without re-running cleanseConfig() on the decoded configuration. Because condition.config is a JSON string during the first cleanse, Yii special config keys such as 'as ...' and 'on ...' can be hidden inside it and, after JSON decoding, are interpreted by Yii as behavior/event configuration during FieldLayout object creation. An attacker with an authenticated control panel session (and a valid CSRF token) can exploit this to execute operating system commands as the PHP/web user.

Vulnerability Details¶

Property	Value
CVE ID	CVE-2026-72778
Type	RCE
CVSS Score	8.8

Proof of Concept¶

Download¶

# Download PoC script
curl -O https://raw.githubusercontent.com/fankh/vulnerability-poc/main/2026/CVE-2026-72778/poc.py

Usage¶

# Run PoC against target
python3 poc.py --target <TARGET_URL>

# With authentication
python3 poc.py --target <TARGET_URL> --username <USER> --password <PASS>

⚠️ Warning: This PoC is for authorized security testing only. It uses detection-only techniques and does not exploit or damage target systems.

Test Lab¶

This repository includes a Docker-based test environment with both vulnerable and patched applications.

Quick Start¶

# Clone and navigate to CVE directory
cd CVE-2026-72778

# Start both applications
docker-compose up -d

# Run tests
./run-tests.sh    # Linux/Mac
./run-tests.ps1   # Windows PowerShell

Application Endpoints¶

Application	URL	Status
Vulnerable App	http://localhost:8080	Shows vulnerability
Patched App	http://localhost:8081	Demonstrates fix

Directory Structure¶

├── README.md           # English documentation
├── README_KO.md        # Korean documentation
├── poc.py              # PoC detection script
├── docker-compose.yml  # Container orchestration
├── run-tests.sh        # Linux/Mac test runner
├── run-tests.ps1       # Windows test runner
├── vulnerable-app/     # Vulnerable version
│   ├── app.py
│   ├── Dockerfile
│   └── requirements.txt
└── patched-app/        # Fixed version
    ├── app.py
    ├── Dockerfile
    └── requirements.txt

References¶

https://github.com/craftcms/cms/security/advisories/GHSA-265m-7826-wjqm
https://www.vulncheck.com/advisories/craft-cms-rc1-before-authenticated-rce-via-condition-config

Generated by PoC Generator on 2026-08-11T23:29:22.718075607

Frequently asked questions¶

What is CVE-2026-72778?¶

CVE-2026-72778 is a High (8.8) vulnerability: Craft CMS versions from 4.0.0-RC1 before 4.18.2 and from 5.0.0-RC1 before 5.10.6 contain…. This entry ships a detection-only PoC and a Docker test lab.

How do I detect CVE-2026-72778?¶

Run the detection-only PoC included with this entry against your Docker test lab to confirm whether a target is affected; pair it with your own IDS logging.

How do I block or mitigate CVE-2026-72778?¶

Upgrade to a fixed version per the vendor advisory; the NVD record lists the affected versions. Use the included PoC to verify your remediation.

For authorized security testing and research only. See the full source and NVD record.