How severe is GHSA-2fph-6v5w-89hh?

No CVSS score has been assigned to GHSA-2fph-6v5w-89hh yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-2fph-6v5w-89hh?

GHSA-2fph-6v5w-89hh affects the following packages: craftcms/cms (Packagist). Ecosystems affected: Packagist.

How do I fix GHSA-2fph-6v5w-89hh?

Update craftcms/cms to 5.9.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2fph-6v5w-89hh is resolved across your whole dependency graph.

How do I detect GHSA-2fph-6v5w-89hh in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for craftcms/cms. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate GHSA-2fph-6v5w-89hh if there is no patch (or I can't update yet)?

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.

How does O3 Security protect against GHSA-2fph-6v5w-89hh?

O3 pinpoints whether GHSA-2fph-6v5w-89hh is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-2fph-6v5w-89hh actively exploited in the wild?

No public exploit code has been indexed for GHSA-2fph-6v5w-89hh yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-2fph-6v5w-89hh?

GHSA-2fph-6v5w-89hh has an EPSS (Exploit Prediction Scoring System) score of 1.0%, placing it in the 59th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-2fph-6v5w-89hh?

GHSA-2fph-6v5w-89hh is classified as CWE-470 (CWE-470). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-2fph-6v5w-89hh published, and has it been updated?

GHSA-2fph-6v5w-89hh was published on March 24, 2026 and was last updated on March 25, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

GHSA-2fph-6v5w-89hh

Craft CMS is Vulnerable to Authenticated Remote Code Execution via Malicious Attached Behavior

Also known asCVE-2026-33157

Published

Mar 24, 2026

Updated

Mar 25, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

1.0%probability of exploitation in next 30 days

Lower Risk59th percentile+0.92%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

🐘craftcms/cms

Real-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

A Remote Code Execution (RCE) vulnerability exists in Craft CMS 5.x and 4.x that bypasses the security fixes for GHSA-7jx7-3846-m7w7 and GHSA-255j-qw47-wjh5. This vulnerability can be exploited by any authenticated user with control panel access.

The existing patches add cleanseConfig() to assembleLayoutFromPost() and various FieldsController actions to strip Yii2 behavior/event injection keys (as and on prefixed keys). However, the fieldLayouts parameter in ElementIndexesController::actionFilterHud() is passed directly to FieldLayout::createFromConfig() without any sanitization, enabling the same behavior injection attack chain.

Impact

Attack Type: Remote Code Execution (RCE)
Authentication Required: Authenticated user with control panel access (accessCp permission)

Vulnerability Details

Root Cause

In ElementIndexesController::actionFilterHud() (line 493-494), the fieldLayouts body parameter is passed to FieldLayout::createFromConfig() without cleanseConfig():

// ElementIndexesController.php:485-494
if ($conditionConfig) {
    $conditionConfig = Component::cleanseConfig($conditionConfig); // conditionConfig IS cleansed
    $condition = $conditionsService->createCondition($conditionConfig);
} else {
    $condition = $this->elementType()::createCondition();
}

if (!empty($fieldLayouts)) {
    // fieldLayouts is NOT cleansed!
    $condition->setFieldLayouts(array_map(
        fn(array $config) => FieldLayout::createFromConfig($config),
        $fieldLayouts
    ));
}

Note the inconsistency: conditionConfig is sanitized with cleanseConfig(), but fieldLayouts is not.

Attack Chain

Send a fieldLayouts array containing config with "as <name>" prefixed keys
FieldLayout::createFromConfig($config) -> new self($config) -> Model::__construct($config)
App::configure($this, $config) processes each key
"as rce" key -> Component::__set("as rce", $value) -> Yii::createObject($value) -> instantiates AttributeTypecastBehavior and attaches it to the FieldLayout
"on *" key -> registers a wildcard event handler
parent::__construct() -> init() -> setTabs([]) -> getAvailableNativeFields() -> trigger(EVENT_DEFINE_NATIVE_FIELDS)
The wildcard handler fires -> AttributeTypecastBehavior::beforeSave() -> typecastAttributes()
$this->owner->typecastBeforeSave -> resolved via Component::__get() -> returns the command string from the behavior's own property
call_user_func([ConsoleProcessus::class, 'execute'], $command) -> shell_exec($command)

Prerequisites

A user account with control panel access

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`craftcms/cms`	≥ 5.6.0&&< 5.9.13	5.9.13

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for craftcms/cms. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update craftcms/cms to 5.9.13 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2fph-6v5w-89hh 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.
How O3 protects you
O3 pinpoints whether GHSA-2fph-6v5w-89hh is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-2fph-6v5w-89hh. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

## Summary A Remote Code Execution (RCE) vulnerability exists in Craft CMS 5.x and 4.x that bypasses the security fixes for GHSA-7jx7-3846-m7w7 and GHSA-255j-qw47-wjh5. This vulnerability can be exploited by any authenticated user with control panel access. The existing patches add `cleanseConfig()` to `assembleLayoutFromPost()` and various `FieldsController` actions to strip Yii2 behavior/event injection keys (`as ` and `on ` prefixed keys). However, the `fieldLayouts` parameter in `ElementIndexesController::actionFilterHud()` is passed directly to `FieldLayout::createFromConfig()` without

O3 Security · Impact-Aware SCA

Is GHSA-2fph-6v5w-89hh in your dependencies?

O3 detects GHSA-2fph-6v5w-89hh across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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