CVE-2026-39938

Analyzed Analyzed - Analysis Complete

Unauthenticated Local File Inclusion in Cacti

Publication date: 2026-06-24

Last updated on: 2026-06-26

Assigner: GitHub, Inc.

Description

Cacti is an open source performance and fault management framework. Versions 1.2.30 and prior have unauthenticated LFI through graph_theme and rrdtool IPC serialization hardening. This issue has been resolved in version 1.2.31.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-06-24

Last Modified

2026-06-26

Generated

2026-07-15

AI Q&A

2026-06-25

EPSS Evaluated

2026-07-14

NVD

CVE-2026-39938

Affected Vendors & Products

Vendor	Product	Version / Range
cacti	cacti	to 1.2.31 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-22	The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
CWE-78	The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

Attack-Flow Graph

Detection Guidance

To detect the CVE-2026-39938 vulnerability on your system, you can check if your Cacti installation is running version 1.2.30 or earlier, as these versions are affected.

You can also attempt to detect exploitation attempts by monitoring HTTP requests for suspicious usage of the `graph_theme` parameter that may include path traversal patterns such as `../` or attempts to access unexpected files.

Example commands to check the installed Cacti version and search for suspicious requests in web server logs include:

Check Cacti version via command line or web interface to confirm if it is 1.2.30 or earlier.
Use grep to search web server logs for suspicious `graph_theme` parameter usage: `grep -i 'graph_theme=' /var/log/apache2/access.log`
Look for path traversal patterns in logs: `grep -E 'graph_theme=.*\.\./' /var/log/apache2/access.log`

If such patterns are found, it may indicate attempts to exploit the LFI vulnerability.

Impact Analysis

This vulnerability has a high severity with a CVSS score of 9.8, indicating it can have a critical impact. Because it allows unauthenticated Local File Inclusion, an attacker can potentially read sensitive files, execute arbitrary code, or disrupt the availability of the system. This can lead to full compromise of the affected system, including confidentiality, integrity, and availability impacts.

Mitigation Strategies

To mitigate this vulnerability, you should upgrade Cacti to version 1.2.31 or later, as this version resolves the unauthenticated local file inclusion issue.

Executive Summary

This vulnerability affects Cacti, an open source performance and fault management framework. Versions 1.2.30 and earlier have an unauthenticated Local File Inclusion (LFI) vulnerability through the graph_theme and rrdtool IPC serialization hardening features. This means that an attacker can exploit these features without authentication to include local files on the server, potentially leading to unauthorized access or code execution. The issue has been fixed in version 1.2.31.

Compliance Impact

The provided information does not specify how the CVE-2026-39938 vulnerability affects compliance with common standards and regulations such as GDPR or HIPAA.

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