Dark Reader is an accessibility browser extension that makes web pages colors dark. Prior to 4.9.126, a website can cause the browser extension's image inversion pipeline to request an unauthenticated icon-like bitmap from a locally running web server when the resource uses a known public-like HTTPS URL and is detected as requiring inversion. This behavior can cross the website-to-local-network boundary and disclose limited information associated with the requested resource.
The darkreader npm package used for website integration is not affected. This issue is fixed in version 4.9.126 for Firefox and version 4.9.128 for other browsers.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Privileges Required
None
No privileges needed
User Interaction
Required
User action required
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
None
No data modification
Availability
None
No disruption
CVSS Vector v3.1