CVE-2023-45818 Cross-site Scripting vulnerability in TinyMCE undo/redo, getContent API, resetContent API, and Autosave plugin
Attackers can execute arbitrary JavaScript via mutation XSS in TinyMCE's undo/redo functionality, requiring users to upgrade the library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2023-45818?
CVE-2023-45818 is a medium-severity cross-site scripting vulnerability in tinymce, published on 19 Oct 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-79
Which versions are affected by CVE-2023-45818?
12 open source packages ship an affected version, including TinyMCE, tinymce/tinymce and tinymce. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
TinyMCE NuGet | All versions | 5.10.8 |
TinyMCE NuGet | All versions | 5.10.8 |
TinyMCE NuGet | From 6.0.0 | 6.7.1 |
TinyMCE NuGet | From 6.0.0 | 6.7.1 |
tinymce/tinymce Packagist | All versions | 5.10.8 |
tinymce/tinymce Packagist | All versions | 5.10.8 |
6 more packages
tinymce/tinymce Packagist | From 6.0.0 | 6.7.1 |
tinymce/tinymce Packagist | From 6.0.0 | 6.7.1 |
tinymce npm | All versions | 5.10.8 |
tinymce npm | All versions | 5.10.8 |
tinymce npm | From 6.0.0 | 6.7.1 |
tinymce npm | From 6.0.0 | 6.7.1 |
Products include Tiny Tinymce.
How do I fix CVE-2023-45818?
Upgrade TinyMCE to a fixed version for your release line: 5.10.8 or 6.7.1.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2023-45818 being exploited?
There is no known exploitation of CVE-2023-45818 in the wild and no public exploit code.
Other vulnerabilities in tinymce
- CVE-2026-47759 TinyMCE Cross-Site Scripting (XSS) vulnerability using through data-mce- prefixed src, href, style attributes
- CVE-2026-47760 TinyMCE Cross-Site Scripting (XSS) vulnerability using sanitization bypass through nested SVGs
- CVE-2026-47761 TinyMCE Cross-Site Scripting (XSS) vulnerability using media plugin `data-mce-object` injection
- CVE-2026-47762 TinyMCE Cross-Site Scripting (XSS) vulnerability through `mce:protected` comments
- CVE-2024-21908 Cross-site scripting vulnerability in TinyMCE
Sources
Also known as GHSA-v65r-p3vv-jjfv, UBUNTU-CVE-2023-45818.