October CMS stored XSS by authenticated backend user with improper configuration
The advisory, in context
Impact
A user with access to the media manager that stores SVG files could create a stored XSS attack against themselves and any other user with access to the media manager when SVG files are supported.
SVG files are supported by default in v3 for convenience; however, this has resulted in multiple mistaken vulnerability reports from security researchers. As per the documentation, if a backend user is not trusted, the advice is to remove the svg extension from the list of supported file types.
Patches
The issue has been patched in v3.5.2 by including an SVG sanister. It is enabled by default for new installations but must be enabled for existing sites in the config/media.php file.
'clean_vectors' => true,
Workarounds
If you cannot upgrade for this patch, follow the pervious advice and remove svg from the supported file types.
References
Credits to:
- Faris Krivic
- Okan Kurtulus
- Aldin Visnjic
- Bug Shankar
For more information
If you have any questions or comments about this advisory:
- Email us at hello@octobercms.com
Affected packages
Start with the recorded fix for your release branch. Check your installed version and test compatibility before upgrading. Fixing this advisory does not rule out other vulnerabilities in the release.
From 3.0.0 before 3.5.2
Fixed in 3.5.2
View affected-version evidence
{
"ranges": [
{
"events": [
{
"introduced": "3.0.0"
},
{
"fixed": "3.5.2"
}
],
"type": "ECOSYSTEM"
}
],
"versions": []
}