# CVE-2026-40082: Cacti session fixation in auth_login.php

Source: https://junglewise.ai/threats/cve-2026-40082-cacti-session-fixation-in-auth-login-php  
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-2026-40082 · Severity: medium · CVSS 5.4 · Published 2026-06-25

Cacti, an open-source network monitoring and fault management framework, is vulnerable to session fixation. An attacker can potentially pre-set a session identifier for a victim; once the victim logs in, the attacker can use that same identifier to hijack the user's active session. This could allow an unauthorized individual to access the monitoring dashboard and view or modify network performance data.

Technologies: [Cacti](https://junglewise.ai/threats/technologies/cacti). Vendors: [Cacti](https://junglewise.ai/threats/vendors/cacti).

## Quick answers

**Is CVE-2026-40082 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-40082 being exploited in the wild.

**How severe is CVE-2026-40082?** Medium severity, with a CVSS score of 5.4, published 25 June 2026.

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

**Is there a fix for CVE-2026-40082?** A patch was published on 2026-06-15: Version 1.2.31 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-40082 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-40082?** Check whether you run Cacti at an affected version. 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

A session fixation vulnerability exists in Cacti's authentication logic within `auth_login.php` and `include/auth.php`. The application fails to call `session_regenerate_id()` after a successful login, meaning the session identifier remains static before and after authentication. An attacker can exploit this by providing a known session ID to a victim (e.g., via subdomain cookie injection or XSS); once the victim authenticates, the attacker can use the fixed ID to hijack the session. While Cacti uses secure cookie flags (HttpOnly, SameSite=Strict), these do not mitigate fixation via same-site vectors. The issue is resolved in version 1.2.31 by ensuring session rotation occurs during the login transition.

## Affected products

- Cacti Cacti <= 1.2.30

## Timeline

- 2026-06-15: patched: Version 1.2.31 released
- 2026-06-18: advisory: GitHub Security Advisory published
- 2026-06-25: disclosed: CVE published to NVD

## References

- [https://github.com/Cacti/cacti/commit/2fa404e70a5702be10682555911228e8e51ba198](https://github.com/Cacti/cacti/commit/2fa404e70a5702be10682555911228e8e51ba198)
- [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-273r-qr93-wgcp](https://github.com/Cacti/cacti/security/advisories/GHSA-273r-qr93-wgcp)

## Related threats

- [Cacti user enumeration via error messages](https://junglewise.ai/threats/cve-2026-49442-cacti-is-an-open-source-performance-and-fault-management)
- [Cacti authenticated stored SQL injection in automation tree rule](https://junglewise.ai/threats/cve-2026-46531-cacti-is-an-open-source-performance-and-fault-management)
- [Cacti input string validation bypass and RCE](https://junglewise.ai/threats/cve-2026-39902-cacti-is-an-open-source-performance-and-fault-management)
- [Cacti package import signature validation bypass](https://junglewise.ai/threats/cve-2026-40941-cacti-package-import-signature-validation-bypass)
- [Cacti path traversal in Report format_file parameter](https://junglewise.ai/threats/cve-2026-40084-cacti-path-traversal-in-report-format-file-parameter)