# CVE-2026-40080: Cacti open redirect in auth_login_redirect

Source: https://junglewise.ai/threats/cve-2026-40080-cacti-open-redirect-in-auth-login-redirect  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-25. Updated: 2026-06-25  
License: CC BY 4.0 with a link back

CVE-2026-40080 · Severity: medium · CVSS 6.1 · Published 2026-06-25

Cacti, an open-source network monitoring and fault management framework, is vulnerable to an open redirect flaw during the login process. By tricking a user into clicking a specially crafted link, an attacker can redirect the user to a malicious external website immediately after they log in. This can be used in phishing campaigns to steal credentials or deliver malware by making the malicious site appear to be a legitimate part of the Cacti application.

## Quick answers

**Is CVE-2026-40080 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-40080 being exploited in the wild.

**How severe is CVE-2026-40080?** Medium severity, with a CVSS score of 6.1, published 25 June 2026.

**Which products and versions are affected?** Cacti Group Cacti <= 1.2.30.

**Is there a fix for CVE-2026-40080?** A patch was published on 2026-04-26: Fix merged into 1.2.x branch via PR #7054 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-40080 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-40080?** Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An open redirect vulnerability exists in Cacti's `auth_login_redirect()` function within `lib/auth.php`. The vulnerability stems from using a simple substring check (`str_contains`) on the `HTTP_REFERER` header against the `CACTI_PATH_URL` constant, rather than performing a proper host validation. If a user's profile is configured to redirect to the referer after login (`login_opts == '1'`), an attacker can provide a referer like `https://evil.com/cacti/` to bypass the check and force a redirection to an external domain. The fix, introduced in version 1.2.31, replaces the substring check with the `validate_redirect_url()` helper function which properly parses URLs and filters external hostnames.

## Affected products

- Cacti Group Cacti <= 1.2.30

## Timeline

- 2026-04-26: patched: Fix merged into 1.2.x branch via PR #7054
- 2026-06-15: advisory: Release of version 1.2.31 containing the fix
- 2026-06-25: disclosed: CVE-2026-40080 published

## References

- [https://github.com/Cacti/cacti/releases/tag/release%2F1.2.31](https://github.com/Cacti/cacti/releases/tag/release%2F1.2.31)
- [https://github.com/Cacti/cacti/security/advisories/GHSA-6gr7-53g8-vchq](https://github.com/Cacti/cacti/security/advisories/GHSA-6gr7-53g8-vchq)