# CVE-2026-56383: Craft CMS - Stored XSS in Table Field via Row Heading Column Type

> An administrator can inject JavaScript into Craft CMS table fields, leading to script execution for other users viewing the page.

- **Severity:** Medium 4.6 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 21 Jun 2026
- **Updated:** 23 Jun 2026
- **Also known as:** GHSA-6j87-m5qx-9fqp

## What is CVE-2026-56383?

CVE-2026-56383 is a medium-severity cross-site scripting vulnerability in craftcms cms, published on 21 Jun 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

### Official description

Craft CMS contains a stored cross-site scripting (XSS) vulnerability in the editableTable.twig component when using the 'Row Heading' column type. The application fails to sanitize input within row heading default values, allowing an attacker with an administrator account (with allowAdminChanges enabled) to inject arbitrary JavaScript that executes when another user views a page containing the affected table field. Affected versions are >= 4.5.0-beta.1 through 4.16.18 and >= 5.0.0-RC1 through 5.8.22; fixed in 4.16.19 and 5.8.23.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-56383?

4 open source packages ship an affected version, including craftcms/cms.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `craftcms/cms` | Packagist | From 4.5.0-beta.1 | 4.16.19 |
| `craftcms/cms` | Packagist | From 4.5.0-beta.1 | 4.16.19 |
| `craftcms/cms` | Packagist | From 5.0.0-RC1 | 5.8.23 |
| `craftcms/cms` | Packagist | From 5.0.0-RC1 | 5.8.23 |

## How do I fix CVE-2026-56383?

Upgrade craftcms/cms to a fixed version for your release line: 4.16.19 or 5.8.23.

## Is CVE-2026-56383 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56383 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-56383 and fix it if it is affected.

What it is: CVE-2026-56383 is a medium-severity cross-site scripting vulnerability in craftcms cms, published on 21 Jun 2026. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56383 exists.

Affected packages and fixed versions:
- craftcms/cms (Packagist): affected from 4.5.0-beta.1; fixed in 4.16.19
- craftcms/cms (Packagist): affected from 4.5.0-beta.1; fixed in 4.16.19
- craftcms/cms (Packagist): affected from 5.0.0-RC1; fixed in 5.8.23
- craftcms/cms (Packagist): affected from 5.0.0-RC1; fixed in 5.8.23

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-56383/ (Markdown: https://insights.sbomify.com/CVE-2026-56383/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-56383
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-56383
- OSV: https://osv.dev/vulnerability/CVE-2026-56383

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-56383/
Summaries are generated and may contain mistakes; the official description above is the record.