Cacti up to 1.2.30 lib/html_utility.php validate_redirect_url HTTP_REFERER

Summaryinfo

A vulnerability described as problematic has been identified in Cacti up to 1.2.30. Impacted is the function validate_redirect_url in the library lib/html_utility.php. Such manipulation of the argument HTTP_REFERER leads to redirect. This vulnerability is traded as CVE-2026-40080. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Cacti up to 1.2.30. It has been rated as problematic. Affected by this issue is the function validate_redirect_url in the library lib/html_utility.php. The manipulation of the argument HTTP_REFERER with an unknown input leads to a redirect vulnerability. Using CWE to declare the problem leads to CWE-601. A web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a Redirect. This simplifies phishing attacks. Impacted is integrity. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-40080 since 04/09/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1204.001 by the MITRE ATT&CK project.

By approaching the search of inurl:lib/html_utility.php it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 1.2.31 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-39585). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Log Management Software

Name

• Cacti

Version

• 1.2.0
• 1.2.1
• 1.2.2
• 1.2.3
• 1.2.4
• 1.2.5
• 1.2.6
• 1.2.7
• 1.2.8
• 1.2.9
• 1.2.10
• 1.2.11
• 1.2.12
• 1.2.13
• 1.2.14
• 1.2.15
• 1.2.16
• 1.2.17
• 1.2.18
• 1.2.19
• 1.2.20
• 1.2.21
• 1.2.22
• 1.2.23
• 1.2.24
• 1.2.25
• 1.2.26
• 1.2.27
• 1.2.28
• 1.2.29
• 1.2.30

License

• open-source

Website

• Product: https://github.com/Cacti/cacti/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Discussion