Cross-site scripting vulnerability in TinyMCE
The advisory, in context
Impact
A cross-site scripting (XSS) vulnerability was discovered in the schema validation logic of the core parser. The vulnerability allowed arbitrary JavaScript execution when inserting a specially crafted piece of content into the editor using the clipboard or editor APIs. This malicious content could then end up in content published outside the editor, if no server-side sanitization was performed. This impacts all users who are using TinyMCE 5.8.2 or lower.
Patches
This vulnerability has been patched in TinyMCE 5.9.0 by ensuring schema validation was still performed after unwrapping invalid elements.
Workarounds
To work around this vulnerability, either:
- Upgrade to TinyMCE 5.9.0 or higher
- Manually sanitize the content using the
BeforeSetContentevent (see below)
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 William Bowling for discovering this vulnerability.
References
https://www.tiny.cloud/docs/release-notes/release-notes59/#securityfixes
For more information
If you have any questions or comments about this advisory:
- Email us at infosec@tiny.cloud
- Open an issue in the TinyMCE repo
Affected packages
Start with the recorded fix for your release branch. Check your installed version and test compatibility before upgrading. Fixing this advisory does not rule out other vulnerabilities in the release.
Earlier releases before 5.9.0
Fixed in 5.9.0
View affected-version evidence
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}Earlier releases before 5.9.0
Fixed in 5.9.0
169 explicitly affected versions
3.4.3.2, 3.4.4, 3.4.5, 3.4.7, 3.5.0, 3.5.0.1, 3.5.1, 3.5.1.1, 3.5.2, 3.5.3, 3.5.4, 3.5.4.1, 3.5.5, 3.5.6, 3.5.7, 3.5.8, 4.0.0, 4.0.1, 4.0.10, 4.0.11, 4.0.13, 4.0.14, 4.0.15, 4.0.16, 4.0.17, 4.0.18, 4.0.19, 4.0.2, 4.0.20, 4.0.21, 4.0.22, 4.0.23, 4.0.24, 4.0.25, 4.0.26, 4.0.27, 4.0.28, 4.0.4, 4.0.5, 4.0.6, 4.0.8, 4.0.9, 4.1.0, 4.1.1, 4.1.10, 4.1.2, 4.1.3, 4.1.4, 4.1.5, 4.1.6, 4.1.7, 4.1.8, 4.1.9, 4.2.0, 4.2.1, 4.2.2, 4.2.3, 4.2.4, 4.2.5, 4.2.6, 4.2.7, 4.2.8, 4.3.0, 4.3.1, 4.3.10, 4.3.11, 4.3.12, 4.3.13, 4.3.2, 4.3.3, 4.3.4, 4.3.6, 4.3.7, 4.3.8, 4.3.9, 4.4.0, 4.4.1, 4.4.2, 4.4.3, 4.5.0, 4.5.1, 4.5.2, 4.5.3, 4.5.4, 4.5.5, 4.5.6, 4.5.7, 4.5.8, 4.6.0, 4.6.1, 4.6.2, 4.6.3, 4.6.4, 4.6.5, 4.6.6, 4.6.7, 4.7.0, 4.7.10, 4.7.11, 4.7.12, 4.7.13, 4.7.3, 4.7.4, 4.7.5, 4.7.6, 4.7.7, 4.7.8, 4.7.9, 4.8.0, 4.8.1, 4.8.2, 4.8.3, 4.8.4, 4.8.5, 4.9.0, 4.9.1, 4.9.10, 4.9.11, 4.9.2, 4.9.3, 4.9.4, 4.9.5, 4.9.6, 4.9.7, 4.9.8, 4.9.9, 5.0.0, 5.0.1, 5.0.10, 5.0.11, 5.0.12, 5.0.13, 5.0.14, 5.0.15, 5.0.16, 5.0.2, 5.0.3, 5.0.4, 5.0.5, 5.0.6, 5.0.7, 5.0.8, 5.0.9, 5.1.0, 5.1.1, 5.1.2, 5.1.3, 5.1.4, 5.1.5, 5.1.6, 5.2.0, 5.2.1, 5.2.2, 5.3.0, 5.3.1, 5.3.2, 5.4.0, 5.4.1, 5.4.2, 5.5.0, 5.5.1, 5.6.0, 5.6.1, 5.6.2, 5.7.0, 5.7.1, 5.8.0, 5.8.1, 5.8.2
View affected-version evidence
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"5.7.1",
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Fixed in 5.9.0
160 explicitly affected versions
4.0.0, 4.0.1, 4.0.10, 4.0.11, 4.0.12, 4.0.13, 4.0.14, 4.0.15, 4.0.16, 4.0.17, 4.0.18, 4.0.19, 4.0.2, 4.0.20, 4.0.21, 4.0.22, 4.0.23, 4.0.24, 4.0.25, 4.0.26, 4.0.27, 4.0.28, 4.0.3, 4.0.4, 4.0.5, 4.0.6, 4.0.7, 4.0.8, 4.0.9, 4.1.0, 4.1.1, 4.1.10, 4.1.2, 4.1.3, 4.1.4, 4.1.5, 4.1.6, 4.1.7, 4.1.8, 4.1.9, 4.2.0, 4.2.1, 4.2.2, 4.2.3, 4.2.4, 4.2.5, 4.2.6, 4.2.7, 4.2.8, 4.3.0, 4.3.1, 4.3.10, 4.3.11, 4.3.12, 4.3.13, 4.3.2, 4.3.3, 4.3.4, 4.3.6, 4.3.7, 4.3.8, 4.3.9, 4.4.0, 4.4.1, 4.4.2, 4.4.3, 4.5.0, 4.5.1, 4.5.12, 4.5.2, 4.5.3, 4.5.4, 4.5.5, 4.5.6, 4.5.7, 4.5.8, 4.5.9, 4.6.0, 4.6.1, 4.6.2, 4.6.3, 4.6.4, 4.6.5, 4.6.6, 4.6.7, 4.7.0, 4.7.1, 4.7.10, 4.7.11, 4.7.12, 4.7.13, 4.7.2, 4.7.3, 4.7.4, 4.7.5, 4.7.6, 4.7.7, 4.7.8, 4.7.9, 4.8.0, 4.8.1, 4.8.2, 4.8.3, 4.8.4, 4.8.5, 4.9.0, 4.9.1, 4.9.10, 4.9.11, 4.9.2, 4.9.3, 4.9.4, 4.9.5, 4.9.6, 4.9.7, 4.9.8, 4.9.9, 5.0.0, 5.0.1, 5.0.10, 5.0.11, 5.0.12, 5.0.13, 5.0.14, 5.0.15, 5.0.16, 5.0.2, 5.0.3, 5.0.4, 5.0.5, 5.0.6, 5.0.7, 5.0.8, 5.0.9, 5.1.0, 5.1.1, 5.1.2, 5.1.3, 5.1.4, 5.1.5, 5.1.6, 5.2.0, 5.2.1, 5.2.2, 5.3.0, 5.3.1, 5.3.2, 5.4.0, 5.4.1, 5.4.2, 5.5.0, 5.5.1, 5.6.0, 5.6.1, 5.6.2, 5.7.0, 5.7.1, 5.8.0, 5.8.1, 5.8.2
View affected-version evidence
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