CVE-2026-40080 – Cacti: Open Redirect via HTTP_REFERER substring check in auth_login_redirect

CVE ID :CVE-2026-40080

Published : June 25, 2026, 10:29 p.m. | 1 hour, 15 minutes ago

Description :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.

Severity: 0.0 | NA

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