CVE-2026-86427 [HIGH] – LibreNMS before 26.8.0 contains an argument injection vulnerability in the graph_title par

LibreNMS before 26.8.0 contains an argument injection vulnerability in the graph_title parameter that allows authenticated attackers to inject arbitrary rrdtool arguments by breaking out of double-quote escaping. Attackers can inject DEF and LINE arguments to read RRD files from unauthorized devices, or use newline injection to execute arbitrary rrdtool commands, bypassing per-device authorization checks.