CVE-2026-40080 — Cacti: Open Redirect via HTTP_REFERER substring check in auth_login_redirect
Cacti is an open source performance and fault management framework. Versions 1.2.30 and prior are vulnerable to Open Redirect through a substring check rather than a host check …
Published: 2026-06-25 · CVSS: 6.1 · CVSS 3.1
Cacti is an open source performance and fault management framework. Versions 1.2.30 and prior are vulnerable to Open Redirect through a substring check rather than a host check at str_contains($referer, CACTI_PATH_URL). When the user's login_opts == '1' (redirect to referer after login), the function used $_SERVER['HTTP_REFERER'] directly. An attacker could craft a referer such as https://evil.com/cacti/. Where CACTI_PATH_URL is /cacti/, the substring matches and the user is redirected to evil.com after login. The pre-existing validate_redirect_url() helper at lib/html_utility.php performed proper validation but was not invoked from auth_login_redirect(). This issue has been fixed in version 1.2.31.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7