{"id":"GHSA-jmqm-f8q4-v7wx","summary":"LibreNMS: Reflected XSS via Proxmox instance/vmid GET parameters injected into document.title JavaScript assignment","details":"### Summary\n`LegacyController.php:75` writes the page title into a `document.title` JS assignment using string interpolation. `apps/proxmox.inc.php` pushes `$vars['instance']` and `$vars['vmid']` (GET params, only `strip_tags()` applied) directly into `$pagetitle`. A single quote terminates the JS string, executing arbitrary script.\n\n### Details\n```php\n// LegacyController.php:75\n$html .= \"\u003cscript\u003e\\ndocument.title = '$title';\\n\u003c/script\u003e\";\n\n// proxmox.inc.php:38,42\n$pagetitle[] = $instance;     // GET ?instance=\n$pagetitle[] = $vars['vmid']; // GET ?vmid=\n```\n\n### PoC\n```\nhttp://target/apps?app=proxmox&instance=%27%3Balert%28document.cookie%29%3B//\n\nConfirmed in response:\ndocument.title = 'Apps - Proxmox - ';alert(document.cookie);// - LibreNMS';\n```\n\n### Fix\n```php\n// LegacyController.php:75\n$html .= \"\u003cscript\u003e\\ndocument.title = \" . json_encode($title) . \";\\n\u003c/script\u003e\";\n```\nAlso wrap `$instance` and `$vars['vmid']` in `htmlspecialchars()` in proxmox.inc.php.\n\n### Prerequisite\nAny authenticated session. Victim must follow a crafted link.","aliases":["CVE-2026-45694"],"modified":"2026-08-12T15:41:04.197622Z","published":"2026-08-12T15:16:22Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-08-12T15:16:22Z","nvd_published_at":null,"cwe_ids":["CWE-79"],"severity":"MODERATE"},"references":[{"type":"WEB","url":"https://github.com/librenms/librenms/security/advisories/GHSA-jmqm-f8q4-v7wx"},{"type":"PACKAGE","url":"https://github.com/librenms/librenms"},{"type":"WEB","url":"https://github.com/librenms/librenms/releases/tag/26.5.0"}],"affected":[{"package":{"name":"librenms/librenms","ecosystem":"Packagist","purl":"pkg:composer/librenms/librenms"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"26.5.0"}]}],"versions":["1.19","1.20","1.20.1","1.21","1.22","1.22.01","1.23","1.24","1.25","1.26","1.27","1.28","1.29","1.30","1.30.01","1.31","1.31.01","1.31.02","1.31.03","1.32","1.32.01","1.33","1.33.01","1.34","1.35","1.36","1.36.01","1.37","1.38","1.39","1.40","1.41","1.42","1.42.01","1.43","1.44","1.45","1.46","1.47","1.48","1.48.1","1.49","1.50","1.50.1","1.51","1.52","1.53","1.53.1","1.54","1.55","1.56","1.57","1.58","1.58.1","1.59","1.60","1.61","1.62","1.62.1","1.62.2","1.63","1.64","1.64.1","1.65","1.65.1","1.66","1.67","1.68","1.69","1.70.0","1.70.1","21.1.0","21.10.0","21.10.1","21.10.2","21.11.0","21.12.0","21.12.1","21.2.0","21.3.0","21.4.0","21.5.0","21.5.1","21.6.0","21.7.0","21.8.0","21.9.0","21.9.1","22.1.0","22.10.0","22.11.0","22.12.0","22.2.0","22.2.1","22.2.2","22.3.0","22.4.0","22.4.1","22.5.0","22.6.0","22.7.0","22.8.0","22.9.0","23.1.0","23.1.1","23.10.0","23.11.0","23.2.0","23.4.0","23.4.1","23.5.0","23.6.0","23.7.0","23.8.0","23.8.1","23.8.2","23.9.0","23.9.1","24.1.0","24.10.0","24.10.1","24.11.0","24.12.0","24.2.0","24.3.0","24.4.0","24.4.1","24.5.0","24.6.0","24.7.0","24.8.0","24.8.1","24.9.0","24.9.1","25.1.0","25.10.0","25.11.0","25.12.0","25.2.0","25.3.0","25.4.0","25.5.0","25.6.0","25.7.0","25.8.0","25.9.0","25.9.1","26.1.0","26.1.1","26.2.0","26.3.0","26.3.1","26.4.0","26.4.1"],"database_specific":{"last_known_affected_version_range":"\u003c= 26.4.0","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-jmqm-f8q4-v7wx/GHSA-jmqm-f8q4-v7wx.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"}]}