How severe is CVE-2026-56383?

No CVSS score has been assigned to CVE-2026-56383 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-56383?

CVE-2026-56383 affects the following packages: craftcms/cms (Packagist), craftcms/cms (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-56383?

Update craftcms/cms to 4.16.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-56383 is resolved across your whole dependency graph.

How do I detect CVE-2026-56383 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-2026-56383 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2026-56383 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-56383 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-2026-56383?

CVE-2026-56383 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 12th 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-2026-56383?

CVE-2026-56383 is classified as Cross-site Scripting (XSS) (CWE-79). 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-2026-56383 published, and has it been updated?

CVE-2026-56383 was published on June 21, 2026 and was last updated on October 27, 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-2026-56383 — cms

Fix: craftcms/cms@7b372de

CVE-2026-56383 is a Cross-site Scripting (XSS) vulnerability in craftcms/cms. A fix is available for craftcms/cms — see the affected versions and patch details below.

Craft CMS - Stored XSS in Table Field via Row Heading Column Type

Also known asGHSA-6j87-m5qx-9fqp

Published

Jun 21, 2026

Updated

Oct 27, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Oct 31, 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.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-56383.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk-0.09%

Lower risk than most CVEs12th percentile — riskier than 12% of all scored CVEsHighest risk

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

Real-World Exposure

2 pkgs affected

🐘craftcms/cms🐘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

A stored Cross-site Scripting (XSS) vulnerability exists in the editableTable.twig component when using the Row Heading column type. The application fails to sanitize input within row headings, allowing an attacker to execute arbitrary JavaScript when another user views a page with the malicious table field.

Prerequisites

An administrator account
allowAdminChanges must be enabled in production, which is against security recommendations.

Steps to Reproduce

Navigate to Settings → Fields and create a new field with Type: Table
Add a Column Heading and set Column Type to Row Heading
In Default Values section, add a row with the following payload:
```
<img src=x onerror="alert('XSS')">
```
Enable Static Rows
Use the field in any object (e.g., user profile fields) → then visit any user’s profile
Notice the XSS execution

Resources

https://github.com/craftcms/cms/commit/7b372de262b8d9d2ce859f32780c3715719b6f5a

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`craftcms/cms`	≥ 4.5.0-beta.1&&< 4.16.19	4.16.19`composer require craftcms/cms:^4.16.19`
🐘Packagist	`craftcms/cms`	≥ 5.0.0-RC1&&< 5.8.23	5.8.23`composer require craftcms/cms:^5.8.23`

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 4.16.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-56383 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

A stored Cross-site Scripting (XSS) vulnerability exists in the `editableTable.twig` component when using the `Row Heading` column type. The application fails to sanitize input within row headings, allowing an attacker to execute arbitrary JavaScript when another user views a page with the malicious table field. ## Prerequisites * An administrator account * `allowAdminChanges` must be enabled in production, which is [against security recommendations](https://craftcms.com/knowledge-base/securing-craft#set-allowAdminChanges-to-false-in-production). ## Steps to Reproduce 1. Navigate to **Settin

O3 Security · Impact-Aware SCA

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