How severe is CVE-2026-56382?

No CVSS score has been assigned to CVE-2026-56382 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-56382?

CVE-2026-56382 affects the following packages: craftcms/cms (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-56382?

Update craftcms/cms to 5.9.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-56382 is resolved across your whole dependency graph.

How do I detect CVE-2026-56382 in my Packagist dependencies?

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.

How do I mitigate CVE-2026-56382 if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Is CVE-2026-56382 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-56382 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 CVE-2026-56382?

CVE-2026-56382 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 58th 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 CVE-2026-56382?

CVE-2026-56382 is classified as Code Injection (CWE-94). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-56382 published, and has it been updated?

CVE-2026-56382 was published on June 21, 2026 and was last updated on August 12, 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

Not in CISA KEV

CVE-2026-56382 — craftcms/cms

CVE-2026-56382 is a Code Injection vulnerability in craftcms/cms. A fix is available for craftcms/cms — see the affected versions and patch details below.

Craft CMS - Remote Code Execution via Missing Config Sanitization in FieldsController

Also known asGHSA-86vw-x4ww-x467

Published

Jun 21, 2026

Updated

Aug 12, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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-2026-56382.

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs58th percentile — riskier than 58% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

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

The actionRenderCardPreview() method in FieldsController passes the fieldLayoutConfig POST parameter directly to Fields::createLayout() without calling Component::cleanseConfig(). This allows Yii2 event handler injection via on eventName keys in the config array, leading to arbitrary code execution.

This is the same vulnerability pattern that was fixed in GHSA-4484-8v2f-5748 (same file, _fldComponent method correctly uses cleanseConfig), GHSA-qx2q-q59v-wf3j (EntryTypesController), and GHSA-2fph-6v5w-89hh (ElementIndexesController).

PoC

As an admin user with a valid session:

POST /admin/actions/fields/render-card-preview HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Cookie: CraftSessionId=<session>

fieldLayoutConfig[on+init]=phpinfo&CRAFT_CSRF_TOKEN=<token>

When the FieldLayout object is constructed, Yii2 processes the on init key as an event handler registration. During Component::init(), the init event is triggered, calling phpinfo(). The phpinfo output (which includes environment variables, potentially containing database credentials and CRAFT_SECURITY_KEY) will appear in the response.

Impact

An authenticated admin can achieve RCE through Yii2 event handler injection. While this requires admin access (same as GHSA-4484-8v2f-5748, which was rated moderate), it allows arbitrary PHP function execution and information disclosure via phpinfo.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`craftcms/cms`	≥ 5.5.0&&< 5.9.14	5.9.14`composer require craftcms/cms:^5.9.14`

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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update craftcms/cms to 5.9.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-56382 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Frequently Asked Questions

The `actionRenderCardPreview()` method in `FieldsController` passes the `fieldLayoutConfig` POST parameter directly to `Fields::createLayout()` without calling `Component::cleanseConfig()`. This allows Yii2 event handler injection via `on eventName` keys in the config array, leading to arbitrary code execution. This is the same vulnerability pattern that was fixed in GHSA-4484-8v2f-5748 (same file, `_fldComponent` method correctly uses `cleanseConfig`), GHSA-qx2q-q59v-wf3j (EntryTypesController), and GHSA-2fph-6v5w-89hh (ElementIndexesController). ## PoC As an admin user with a valid sessio

O3 Security · Impact-Aware SCA

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