# CVE-2020-12648: TinyMCE cross-site scripting in parser

Source: https://junglewise.ai/threats/cve-2020-12648-tinymce-cross-site-scripting-in-parser  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2020-08-11. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2020-12648 · Severity: low · CVSS 3.1 · Published 2020-08-11

TinyMCE is a popular rich-text editor embedded in web applications. A cross-site scripting vulnerability in its HTML parser allowed attackers to inject malicious JavaScript code when content was pasted into the editor or inserted via APIs, potentially compromising user sessions and stealing data from anyone using an unpatched version.

Technologies: [tinymce (npm)](https://junglewise.ai/threats/technologies/tinymce). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2020-12648 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2020-12648 being exploited in the wild.

**How severe is CVE-2020-12648?** Low severity, with a CVSS score of 3.1, published 11 August 2020.

**Which products and versions are affected?** tinymce (npm) SEMVER:introduced=0,fixed=4.9.11.

**Is there a fix for CVE-2020-12648?** Yes. tinymce (npm): upgrade to 4.9.11 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2020-12648 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2020-12648?** Check whether you run tinymce (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- tinymce (npm): upgrade to 4.9.11 or later

  ```sh
  npm install tinymce@4.9.11
  ```


## Technical details

The vulnerability is a cross-site scripting (XSS) flaw in the core HTML parser and sanitization logic. When specially crafted HTML content (specifically malformed iframe elements) was inserted into the editor via clipboard or programmatic APIs, the parser failed to properly sanitize the content, allowing arbitrary JavaScript execution. The attack requires user interaction (pasting content or triggering an API call with malicious payload) but no authentication. The issue was patched in TinyMCE 4.9.11 and 5.4.1 with improved HTML parsing and sanitization, and also by adding iframe to the special elements list in the parser schema.

## Affected products

- Tiny Technologies TinyMCE 4.9.10 and earlier; 5.0.0 through 5.4.0

## Identifiers

- CVE-2020-12648
- GHSA-vrv8-v4w8-f95h

## Timeline

- 2020-08-10: disclosed
- 2020-08-10: patched: Patched in TinyMCE 4.9.11 and 5.4.1
- 2020-07-04: other: Parsing fix merged in PR #5843

## References

- [https://github.com/tinymce/tinymce/security/advisories/GHSA-vrv8-v4w8-f95h](https://github.com/tinymce/tinymce/security/advisories/GHSA-vrv8-v4w8-f95h)
- [https://github.com/tinymce/tinymce/pull/5843](https://github.com/tinymce/tinymce/pull/5843)

## Related threats

- [TinyMCE media plugin stored cross-site scripting](https://junglewise.ai/threats/cve-2026-116675-tinymce-is-an-open-source-rich-text-editor-from-7-9-3-until-7-9)
- [PYSEC-2026-1301 - TinyMCE Cross-Site Scripting (XSS) vulnerability using noneditable_regexp option](https://junglewise.ai/threats/cve-2024-38356-tinymce-cross-site-scripting-in-noneditable-regexp)
- [PYSEC-2026-1302 - TinyMCE Cross-Site Scripting (XSS) vulnerability using noscript elements](https://junglewise.ai/threats/cve-2024-38357-tinymce-cross-site-scripting-in-noscript-element-parsing)
- [PYSEC-2026-632 - Cross-site scripting vulnerability in TinyMCE plugins](https://junglewise.ai/threats/cve-2024-21910-tinymce-cross-site-scripting-in-image-and-link-plugins)
- [Tiny Technologies TinyMCE stored XSS via forged mce:protected comments](https://junglewise.ai/threats/cve-2026-47762-tiny-technologies-tinymce-stored-xss-via-forged-mce-protected)