Impact
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 $file->store() with no server-side validation of MIME type, extension, or file content.
Any authenticated user with access to a page embedding <livewire:markdown-editor> can upload files of any type (.html, .svg, .js, .php, .exe, etc.) to the disk configured by livewire-markdown-editor.disk. When that disk is a public cloud bucket (S3, DigitalOcean Spaces, Cloudflare R2, Scaleway Object Storage — the common configuration when FILESYSTEM_DISK points to such a disk), uploaded files are served publicly with a guessed Content-Type header.
The consequences include:
- Stored XSS on the storage domain via uploaded
.html or .svg files
- Phishing page hosting on the application's own storage domain (trust laundering)
- Malware distribution from a domain users associate with the application
- Markdown injection in the editor output via crafted filenames (the client-supplied
getClientOriginalName() value was inserted verbatim into the markdown)
A real-world exploitation of this vulnerability was observed in production on a community platform using this package.
Patches
Upgrade to v1.3 or later.
Workarounds
If developers cannot upgrade immediately, disable the upload UI on every instance of the editor by passing :show-upload="false":
<livewire:markdown-editor wire:model="content" :show-upload="false" />
This hides the file input and prevents the vulnerable code path from being reached.
Resources
References
Impact
All versions of
mckenziearts/livewire-markdown-editorprior to v1.3 contain a critical arbitrary file upload vulnerability in theMarkdownEditor::updatedAttachments()Livewire handler. The handler calls$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 bylivewire-markdown-editor.disk. When that disk is a public cloud bucket (S3, DigitalOcean Spaces, Cloudflare R2, Scaleway Object Storage — the common configuration whenFILESYSTEM_DISKpoints to such a disk), uploaded files are served publicly with a guessedContent-Typeheader.The consequences include:
.htmlor.svgfilesgetClientOriginalName()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":This hides the file input and prevents the vulnerable code path from being reached.
Resources
References