GHSA-GXXH-8VCJ-W2MH

Workarounds

If developers cannot upgrade immediately, disable the upload UI on every instance of the editor by passing :show-upload="false":

  <livewire:markdown-editor wire:model="content" :show-upload="false" />

This hides the file input and prevents the vulnerable code path from being reached.

Resources

• Patch commit: https://github.com/mckenziearts/livewire-markdown-editor/pull/12
• Release: https://github.com/mckenziearts/livewire-markdown-editor/releases/tag/v1.3
• CWE-434: https://cwe.mitre.org/data/definitions/434.html
• CWE-79: https://cwe.mitre.org/data/definitions/79.html

All versions of mckenziearts/livewire-markdown-editor prior to v1.3 contain a critical arbitrary file upload vulnerability in the MarkdownEditor::updatedAttachments() Livewire handler. The handler calls $file->store() with no server-side validation of MIME type, extension, or file content.

Any authenticated user with access to a page embedding <livewire:markdown-editor> can upload files of any type (.html, .svg, .js, .php, .exe, etc.) to the disk configured by livewire-markdown-editor.disk. When that disk is a public cloud bucket (S3, DigitalOcean Spaces, Cloudflare R2, Scaleway Object Storage, the common configuration when FILESYSTEM_DISK points to such a disk), uploaded files are served publicly with a guessed Content-Type header.

The consequences include:

• Stored XSS on the storage domain via uploaded .html or .svg files
• Phishing page hosting on the application's own storage domain (trust laundering)
• Malware distribution from a domain users associate with the application
• Markdown injection in the editor output via crafted filenames (the client-supplied getClientOriginalName() value was inserted verbatim into the markdown)

A real-world exploitation of this vulnerability was observed in production on a community platform using this package.

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

GHSA-GXXH-8VCJ-W2MH has a CVSS score of 7.1 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.3); upgrading removes the vulnerable code path.

Kodem intelligence

Upgrade to v1.3 or later.

1. What is GHSA-GXXH-8VCJ-W2MH? GHSA-GXXH-8VCJ-W2MH is a high-severity cross-site scripting (XSS) vulnerability in mckenziearts/livewire-markdown-editor (composer), affecting versions < 1.3. It is fixed in 1.3. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is GHSA-GXXH-8VCJ-W2MH? GHSA-GXXH-8VCJ-W2MH has a CVSS score of 7.1 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of mckenziearts/livewire-markdown-editor are affected by GHSA-GXXH-8VCJ-W2MH? mckenziearts/livewire-markdown-editor (composer) versions < 1.3 is affected.
4. Is there a fix for GHSA-GXXH-8VCJ-W2MH? Yes. GHSA-GXXH-8VCJ-W2MH is fixed in 1.3. Upgrade to this version or later.
5. Is GHSA-GXXH-8VCJ-W2MH exploitable, and should I be worried? Whether GHSA-GXXH-8VCJ-W2MH is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether GHSA-GXXH-8VCJ-W2MH is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix GHSA-GXXH-8VCJ-W2MH? Upgrade mckenziearts/livewire-markdown-editor to 1.3 or later.