# CVE-2024-21908: Cross-site scripting vulnerability in TinyMCE

> An attacker can inject malicious HTML into TinyMCE, leading to arbitrary JavaScript execution in other users' browsers.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **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:** Yes
- **Published:** 3 Jan 2024
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-5h9g-x5rv-25wg, UBUNTU-CVE-2024-21908

## What is CVE-2024-21908?

CVE-2024-21908 is a medium-severity cross-site scripting vulnerability in tiny:tinymce, published on 3 Jan 2024. 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 versions before 5.9.0 are affected by a stored cross-site scripting vulnerability. An unauthenticated and remote attacker could insert crafted HTML into the editor resulting in arbitrary JavaScript execution in another user's browser.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2024-21908?

6 open source packages ship an affected version, including TinyMCE, tinymce/tinymce and tinymce. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `TinyMCE` | NuGet | All versions | 5.9.0 |
| `TinyMCE` | NuGet | All versions | 5.9.0 |
| `tinymce/tinymce` | Packagist | All versions | 5.9.0 |
| `tinymce/tinymce` | Packagist | All versions | 5.9.0 |
| `tinymce` | npm | All versions | 5.9.0 |
| `tinymce` | npm | All versions | 5.9.0 |

Products: Tiny Tinymce.

## How do I fix CVE-2024-21908?

Upgrade TinyMCE to 5.9.0 or later.

## Is CVE-2024-21908 being exploited?

There is no known exploitation of CVE-2024-21908 in the wild and no public exploit code.

## Other vulnerabilities in tiny:tinymce

- [CVE-2026-47759](https://insights.sbomify.com/CVE-2026-47759/): TinyMCE Cross-Site Scripting (XSS) vulnerability using through data-mce- prefixed src, href, style attributes (high 8.7)
- [CVE-2026-47760](https://insights.sbomify.com/CVE-2026-47760/): TinyMCE Cross-Site Scripting (XSS) vulnerability using sanitization bypass through nested SVGs (high 8.7)
- [CVE-2026-47761](https://insights.sbomify.com/CVE-2026-47761/): TinyMCE Cross-Site Scripting (XSS) vulnerability using media plugin `data-mce-object` injection (high 8.7)
- [CVE-2026-47762](https://insights.sbomify.com/CVE-2026-47762/): TinyMCE Cross-Site Scripting (XSS) vulnerability through `mce:protected` comments (high 8.7)
- [CVE-2024-21910](https://insights.sbomify.com/CVE-2024-21910/): Cross-site scripting vulnerability in TinyMCE plugins (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-21908 and fix it if it is affected.

What it is: CVE-2024-21908 is a medium-severity cross-site scripting vulnerability in tiny:tinymce, published on 3 Jan 2024. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2024-21908 in the wild and no public exploit code.

Affected packages and fixed versions:
- TinyMCE (NuGet): affected all versions; fixed in 5.9.0
- TinyMCE (NuGet): affected all versions; fixed in 5.9.0
- tinymce/tinymce (Packagist): affected all versions; fixed in 5.9.0
- tinymce/tinymce (Packagist): affected all versions; fixed in 5.9.0
- tinymce (npm): affected all versions; fixed in 5.9.0
- tinymce (npm): affected all versions; fixed in 5.9.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2024-21908/ (Markdown: https://insights.sbomify.com/CVE-2024-21908/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-21908
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-21908
- OSV: https://osv.dev/vulnerability/CVE-2024-21908

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-21908/
Summaries are generated and may contain mistakes; the official description above is the record.