IPFire < v2.29 Stored XSS via Default IP Search Value

IPFire versions prior to 2.29 (Core Update 198) contain a stored cross-site scripting (XSS) vulnerability that allows an authenticated attacker to inject arbitrary JavaScript code through the pienumber parameter when updating the default firewall IP search values. When a user updates these defaults, the application issues an HTTP POST request to /cgi-bin/logs.cgi/firewalllogip.dat with the default number of IPs in the pienumber parameter. The value of this parameter is stored and later rendered in the web interface without proper sanitation or encoding, allowing injected scripts to execute in the context of other users who view the affected page.