GHSA-GXXH-8VCJ-W2MH
Vulnerability from github – Published: 2026-05-04 22:11 – Updated: 2026-05-04 22:11Impact
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
.htmlor.svgfiles - 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.
Patches
Upgrade to v1.3 or later.
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
{
"affected": [
{
"package": {
"ecosystem": "Packagist",
"name": "mckenziearts/livewire-markdown-editor"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.3"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-434",
"CWE-79"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-04T22:11:05Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "### Impact\nAll 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-\u003estore()` with no server-side validation of MIME type, extension, or file content.\n\nAny authenticated user with access to a page embedding `\u003clivewire:markdown-editor\u003e` 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 \u2014 the common configuration when `FILESYSTEM_DISK` points to such a disk), uploaded files are served publicly with a guessed `Content-Type` header.\n\nThe consequences include:\n\n- **Stored XSS** on the storage domain via uploaded `.html` or `.svg` files\n- **Phishing page hosting** on the application\u0027s own storage domain (trust laundering)\n- **Malware distribution** from a domain users associate with the application\n- **Markdown injection** in the editor output via crafted filenames (the client-supplied `getClientOriginalName()` value was inserted verbatim into the markdown)\n\nA real-world exploitation of this vulnerability was observed in production on a community platform using this package.\n\n### Patches\n\nUpgrade to **v1.3** or later.\n\n### Workarounds\n\nIf developers cannot upgrade immediately, disable the upload UI on every instance of the editor by passing `:show-upload=\"false\"`:\n\n```blade\n \u003clivewire:markdown-editor wire:model=\"content\" :show-upload=\"false\" /\u003e\n```\n\nThis hides the file input and prevents the vulnerable code path from being reached.\n\n### Resources\n\n- Patch commit: https://github.com/mckenziearts/livewire-markdown-editor/pull/12\n- Release: https://github.com/mckenziearts/livewire-markdown-editor/releases/tag/v1.3\n- CWE-434: https://cwe.mitre.org/data/definitions/434.html\n- CWE-79: https://cwe.mitre.org/data/definitions/79.html",
"id": "GHSA-gxxh-8vcj-w2mh",
"modified": "2026-05-04T22:11:05Z",
"published": "2026-05-04T22:11:05Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/mckenziearts/livewire-markdown-editor/security/advisories/GHSA-gxxh-8vcj-w2mh"
},
{
"type": "WEB",
"url": "https://github.com/mckenziearts/livewire-markdown-editor/commit/1e60eaa5781e89704e112425f832774be85cd71f"
},
{
"type": "PACKAGE",
"url": "https://github.com/mckenziearts/livewire-markdown-editor"
},
{
"type": "WEB",
"url": "https://github.com/mckenziearts/livewire-markdown-editor/releases/tag/v1.3"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N",
"type": "CVSS_V3"
}
],
"summary": "livewire-markdown-editor has arbitrary file upload that allows stored XSS via attachment handler"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.