# CVE-2026-39900: Cacti reflected XSS in auth_profile.php via tab parameter

Source: https://junglewise.ai/threats/cve-2026-39900-cacti-reflected-xss-in-auth-profile-php-via-tab-parameter  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-24. Updated: 2026-06-24  
License: CC BY 4.0 with a link back

CVE-2026-39900 · Severity: info · CVSS 5.3 · Published 2026-06-24

Cacti, an open-source network monitoring and fault management framework, is vulnerable to a security flaw where malicious code can be injected into a user's browser. By tricking a user into clicking a specially crafted link, an attacker could execute unauthorized scripts in the context of the user's session. This could lead to the theft of sensitive information or unauthorized actions being performed on the user's behalf within the Cacti application.

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

## Quick answers

**Is CVE-2026-39900 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-39900 being exploited in the wild.

**How severe is CVE-2026-39900?** Informational severity, with a CVSS score of 5.3, published 24 June 2026.

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

**Is there a fix for CVE-2026-39900?** A patch was published on 2026-04-26: Fix committed to repository Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-39900 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-39900?** 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 reflected cross-site scripting (XSS) vulnerability exists in Cacti versions 1.2.30 and prior. The 'tab' parameter in auth_profile.php is rendered directly into a JavaScript context without sufficient escaping or validation. An attacker can exploit this by crafting a URL containing a malicious payload in the 'tab' parameter and persuading a logged-in user to visit it. The fix, introduced in version 1.2.31, implements strict input validation using a regular expression (restricting input to alphanumeric characters and underscores) and ensures the output is safely encoded using json_encode.

## Affected products

- Cacti Cacti <= 1.2.30

## Timeline

- 2026-04-26: patched: Fix committed to repository
- 2026-06-18: advisory: GitHub Security Advisory published
- 2026-06-24: disclosed: CVE published to NVD

## References

- [https://github.com/Cacti/cacti/commit/891344a5c10b8687a3d2a5d26e6de20f13069e2a](https://github.com/Cacti/cacti/commit/891344a5c10b8687a3d2a5d26e6de20f13069e2a)
- [https://github.com/Cacti/cacti/security/advisories/GHSA-34rf-frc3-v48r](https://github.com/Cacti/cacti/security/advisories/GHSA-34rf-frc3-v48r)

## 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)