Vulnerability · Published Jun 25, 2026 · Assigned by GitHub_M
CVE-2026-40080Cacti: Open Redirect via HTTP_REFERER substring check in auth_login_redirect
Medium 6.1
In plain English
A medium-severity open redirect in cacti from Cacti. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | cacti | no fix listed | DEBIAN-CVE-2026-40080 |
| Debian:13 | cacti | no fix listed | DEBIAN-CVE-2026-40080 |
| Debian:14 | cacti | 1.2.31+ds1-1 | DEBIAN-CVE-2026-40080 |
| Ubuntu:24.04:LTS | cacti | no fix listed | UBUNTU-CVE-2026-40080 |
| Ubuntu:25.10 | cacti | no fix listed | UBUNTU-CVE-2026-40080 |
| Ubuntu:26.04:LTS | cacti | no fix listed | UBUNTU-CVE-2026-40080 |
| Ubuntu:26.10 | cacti | no fix listed | UBUNTU-CVE-2026-40080 |
Affected products (as reported)
Weakness: CWE-601 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
References
- https://github.com/Cacti/cacti/security/advisories/GHSA-6gr7-53g8-vchq x_refsource_CONFIRM
- https://github.com/Cacti/cacti/releases/tag/release%2F1.2.31 x_refsource_MISC