CVE-2024-22191 (avo): avo vulnerable to stored cross-site scripting (XSS) in key_value field

Ruby Security Advisory

### Summary

A **stored cross-site scripting (XSS)** vulnerability was found in
the **key_value** field of Avo v3.2.3. This vulnerability could allow
an attacker to execute arbitrary JavaScript code in the victim’s browser.

### Details

The value of the key_value is inserted directly into the HTML code.
In the current version of Avo (possibly also older versions), the
value is not properly sanitized before it is inserted into the HTML code.

This vulnerability can be exploited by an attacker to inject malicious
JavaScript code into the key_value field. When a victim views the page
containing the malicious code, the code will be executed in their browser.

In [avo/fields/common/key_value_component.html.erb](
the value is taken in lines **38** and **49** and seems to be
interpreted directly as html in lines **44** and **55**.

### PoC


To reproduce the vulnerability, follow these steps:

1. Edit an entry with a key_value field.

2. Enter the following payload into the value field:
“`POC\”> Outside-tag