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Security Advisories: MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLTI3Z20tZ2hyOS00djk1

Cross-site scripting vulnerability in TinyMCE

Impact

A cross-site scripting (XSS) vulnerability was discovered in: the core parser, paste and visualchars plugins. The vulnerability allowed arbitrary JavaScript execution when inserting a specially crafted piece of content into the editor via the clipboard or APIs. This impacts all users who are using TinyMCE 4.9.6 or lower and TinyMCE 5.1.3 or lower.

Patches

This vulnerability has been patched in TinyMCE 4.9.7 and 5.1.4 by improved parser logic and HTML sanitization.

Workarounds

The workarounds available are:

• disable the impacted plugins
• manually sanitize the content using the BeforeSetContent event (see below)
• upgrade to either TinyMCE 4.9.7 or TinyMCE 5.1.4

Example: Manually sanitize content

editor.on('BeforeSetContent', function(e) {
  var sanitizedContent = ...; // Manually sanitize content here
  e.content = sanitizedContent;
});

Acknowledgements

Tiny Technologies would like to thank Michał Bentkowski for discovering this vulnerability.

References

https://www.tiny.cloud/docs/release-notes/release-notes514/#securityfixes

For more information

If you have any questions or comments about this advisory:

• Open an issue in the TinyMCE repo
• Email us at [email protected]

Permalink: https://github.com/advisories/GHSA-27gm-ghr9-4v95
JSON: https://advisories.ecosyste.ms/api/v1/advisories/MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLTI3Z20tZ2hyOS00djk1
Source: GitHub Advisory Database
Origin: Unspecified
Severity: High
Classification: General
Published: almost 4 years ago
Updated: 5 months ago

Identifiers: GHSA-27gm-ghr9-4v95, CVE-2020-17480
References:

• https://github.com/tinymce/tinymce/security/advisories/GHSA-27gm-ghr9-4v95
• https://nvd.nist.gov/vuln/detail/CVE-2020-17480
• https://portswigger.net/daily-swig/xss-vulnerability-patched-in-tinymce
• https://www.tiny.cloud/docs/release-notes/release-notes514/#securityfixes
• https://github.com/advisories/GHSA-27gm-ghr9-4v95

Affected Packages