Joomla! ChronoForums 2.0.11 avatar function is vulnerable to local file inclusion through unauthenticated path traversal attacks. This enables an attacker to read arbitrary files, for example the Joomla! configuration file which contains credentials.
View the template here CVE-2021-28377.yaml
References:
https://nvd.nist.gov/vuln/detail/CVE-2021-28377