Cross-site scripting vulnerability in TinyMCE

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

not scored

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Impact A cross-site scripting (XSS) vulnerability was discovered in the URL sanitization logic of the core parser for form elements. The vulnerability allowed arbitrary JavaScript execution when inserting a specially crafted piece of content into the editor using the clipboard or APIs, and then submitting the form. However, as TinyMCE does not allow forms to be submitted while editing, the vulnerability could only be triggered when the content was previewed or rendered outside of the editor. This impacts all users who are using TinyMCE 5.7.0 or lower. Patches This vulnerability has been patched in TinyMCE 5.7.1 by improved URL sanitization logic. Workarounds To work around this vulnerability, either: - Upgrade to TinyMCE 5.7.1 or higher - Manually sanitize form URL attributes using a TinyMCE node filter. - Disable form elements in your content using the invalidelements setting. Example: Sanitizing using a node filter Example: Using invalidelements Acknowledgements Tiny Technologies…

Published by the source

28 May 2021, 19:18 UTC

Last modified by the source

9 Jan 2023, 05:05 UTC

Source last checked

26 Oct 2026, 12:15 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-5vm8-hhgr-jcjp

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-5vm8-hhgr-jcjp

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# Patch Next advisory brief: GHSA-5vm8-hhgr-jcjp

Advisory: Cross-site scripting vulnerability in TinyMCE
IDs: GHSA-5vm8-hhgr-jcjp
Record: https://patchnext.com/advisories/ghsa-5vm8-hhgr-jcjp (revision 2, source checked 26 Oct 2026, 12:15 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Unrated
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: tinymce 5.7.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm tinymce: affected < 5.7.1; fixed in 5.7.1

## Suggested inspection (read-only)
- `npm ls tinymce --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on tinymce.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-5vm8-hhgr-jcjp (OSV record GHSA-5vm8-hhgr-jcjp lists affected ranges: npm tinymce >=0 <5.7.1 (fixed))
- Verified: https://github.com/advisories/GHSA-5vm8-hhgr-jcjp (GitHub-reviewed advisory GHSA-5vm8-hhgr-jcjp lists affected ranges: npm tinymce >=0 <5.7.1)

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