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PatchSiren cyber security CVE debrief

CVE-2026-40084 Cacti CVE debrief

CVE-2026-40084 is a Path Traversal vulnerability in Cacti, a popular open-source performance and fault management framework. The vulnerability affects versions 1.2.30 and prior, allowing attackers to read arbitrary files from the filesystem. This is achieved through a two-stage process: first, an attacker injects a malicious file format into the database, and then, the application reads the file without proper validation. The issue has been fixed in version 1.2.31. Users of affected versions should update to the latest version to mitigate this vulnerability.

Vendor
Cacti
Product
Unknown
CVSS
MEDIUM 6.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-25
Original CVE updated
2026-06-29
Advisory published
2026-06-25
Advisory updated
2026-06-29

Who should care

System administrators and security teams responsible for Cacti installations should be aware of this vulnerability. Given the medium CVSS score of 6.5, this vulnerability may not be considered critical, but it still poses a risk, especially in environments where an attacker has legitimate access to the system. Updating to version 1.2.31 or later is recommended.

Technical summary

The vulnerability occurs in two stages. First, in lib/html_reports.php at line 283, $save['format_file'] = $post['format_file'] is stored directly into the database without validation. Then, in lib/reports.php at line 667, CACTI_PATH_FORMATS . '/' . $format_file is concatenated, and line 670 calls file($format_file), allowing for arbitrary file reads. The CVSS vector is CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N, indicating a medium severity vulnerability.

Defensive priority

Medium priority should be given to updating Cacti installations to version 1.2.31 or later. While the CVSS score is medium, the vulnerability's impact on confidentiality is high, making it important to address.

Recommended defensive actions

  • Update Cacti to version 1.2.31 or later
  • Review and validate user input for file formats
  • Monitor for suspicious file access patterns
  • Implement additional security measures to restrict file system access
  • Conduct regular security audits and vulnerability assessments

Evidence notes

The CVE record and NVD detail provide comprehensive information about the vulnerability. The CVE was published on 2026-06-25 and modified on 2026-06-29. The vulnerability has been analyzed and has a CWE-22 classification.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-40084 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-40084

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-40084 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-40084

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.