GHSA-fx3v-553x-3c4q
Stored XSS by authenticated backend user with access to upload files
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Packagist | october/backend | >= 1.0.319, < 1.0.469 | 1.0.469 |
Details
As written in the advisory (Markdown source, shown as plain text).
### Impact
Backend users with access to upload files were permitted to upload SVG files without any sanitization applied to the uploaded files. Since SVG files support being parsed as HTML by browsers, this means that they could theoretically upload Javascript that would be executed on a path under the website's domain (i.e. /storage/app/media/evil.svg), but they would have to convince their target to visit that location directly in the target's browser as the backend does not display SVGs inline anywhere, SVGs are only displayed as image resources in the backend and are thus unable to be executed.
### Patches
Issue has been patched in Build 469 (v1.0.469) & v1.1.0.
### Workarounds
Apply https://github.com/octobercms/library/commit/80aab47f044a2660aa352450f55137598f362aa4 to your installation manually if unable to upgrade to Build 469 or v1.1.0.
### References
Reported by [Hoan Hoang](https://github.com/hoanhp)
### For more information
If you have any questions or comments about this advisory:
* Email us at [[email protected]](mailto:[email protected])
### Threat assessment:
<img width="1107" alt="Screen Shot 2020-10-10 at 1 47 49 PM" src="https://user-images.githubusercontent.com/7253840/95663787-378f2b80-0aff-11eb-8dfc-b97d162939da.png">
References
External links from the advisory. They lead to third-party sites.