CVE-2026-40080

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.

CVSS v3.1 Score

6.1

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0015

Probability of exploitation

0.05%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-601 CWE-601

Affected Products

Vendor	Product	Versions
cacti	cacti	< 1.2.31

References

Advisories & Patches

https://github.com/Cacti/cacti/security/advisories/GHSA-6gr7-53g8-vchq https://github.com/Cacti/cacti/security/advisories/GHSA-6gr7-53g8-vchq

Exploits

https://github.com/Cacti/cacti/security/advisories/GHSA-6gr7-53g8-vchq https://github.com/Cacti/cacti/security/advisories/GHSA-6gr7-53g8-vchq

Other References

https://github.com/Cacti/cacti/releases/tag/release%2F1.2.31

Frequently Asked Questions

What is CVE-2026-40080? +

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. It has a CVSS v3.1 base score of 6.1 (MEDIUM).

How severe is CVE-2026-40080? +

CVE-2026-40080 has a CVSS v3.1 score of 6.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0015, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-40080? +

CVE-2026-40080 affects products from cacti, specifically: cacti. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-40080? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2024-53995

SickChill is an automatic video library manager for TV shows. A user-controlled `login` endpoint's `next_` parameter takes arbitrary content. Prior …

CVE-2026-40299

next-intl provides internationalization for Next.js. Applications using the `next-intl` middleware prior to version 4.9.1with `localePrefix: 'as-needed'` could construct URLs where …

CVE-2026-42350

Kargo manages and automates the promotion of software artifacts. Prior to versions 1.7.10, 1.8.13, 1.9.8, and 1.10.2, Kargo is vulnerable …

CVE-2026-10839

Open redirection vulnerability in the authentication system allows an attacker to use manipulated values in the X-Forwarded-Host header to alter …

CVE-2026-10837

Open redirection vulnerability due to insufficient validation of the X-Forwarded-Host HTTP header. An attacker could create manipulated links that, when …

CVE-2025-25300

smartbanner.js is a customizable smart app banner for iOS and Android. Prior to version 1.14.1, clicking on smartbanner `View` link …