An issue was discovered in OpenNDS Captive Portal before version 10.1.2. When the custom unescape callback is enabled, attackers can execute arbitrary OS commands by inserting them into the URL portion of HTTP GET requests. Affected OpenNDS Captive Portal before version 10.1.2 fixed in OpenWrt master, OpenWrt 23.05 and OpenWrt 22.03 on 28. August 2023 by updating OpenNDS to version 10.1.3.
The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.