CVE-2021-41174 log

Severity Medium
Remote Yes
Type Cross-site scripting
A security issue has been found in Grafana before version 8.2.3. If an attacker is able to convince a victim to visit a URL referencing a vulnerable page, arbitrary JavaScript content may be executed within the context of the victim's browser.

The user visiting the malicious link must be unauthenticated and the link must be for a page that contains the login button in the menu bar.

There are two ways an unauthenticated user can open a page in Grafana that contains the login button:
- Anonymous authentication is enabled. This means all pages in Grafana would be open for the attack.
- The link is to an unauthenticated page. The following pages are vulnerable:
  - /dashboard-solo/snapshot/*
  - /dashboard/snapshot/*
  - /invite/:code

The url has to be crafted to exploit AngularJS rendering and contain the interpolation binding for AngularJS expressions. AngularJS uses double curly braces for interpolation binding: {{ }}

An example of an expression would be: "{{constructor.constructor(‘alert(1)’)()}}". This can be included in the link URL like this:'alert(1)')()%7D%7D?orgId=1

When the user follows the link and the page renders, the login button will contain the original link with a query parameter to force a redirect to the login page. The URL is not validated and the AngularJS rendering engine will execute the JavaScript expression contained in the URL.
Group Package Affected Fixed Severity Status Ticket
AVG-2517 grafana 8.2.2-1 8.2.3-1 Medium Fixed
Date Advisory Group Package Severity Type
05 Nov 2021 ASA-202111-5 AVG-2517 grafana Medium cross-site scripting

To mitigate the issue, a reverse proxy or similar can be used to block access to block the literal string "{{" in the path.