CVE-2026-65638
Received Received - Intake

Command Injection in ConfigServer Security & Firewall

Publication date: 2026-09-10

Last updated on: 2026-09-10

Assigner: HackerOne

Description
Improper escaping of a request URL in ConfigServer Security & Firewall allows an unauthenticated remote attacker to execute arbitrary commands as the CSF service account via shell command injection. The vulnerability affects versions of the software originally distributed by ConfigServer, as well as versions of the WebPros-maintained fork that contain the vulnerable code. WebPros has addressed the vulnerability in version 16.30. Other forks or independently maintained versions of ConfigServer Security & Firewall (CSF) may also be affected and should be evaluated independently.

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Meta Information

Published
2026-09-10
Last Modified
2026-09-10
Generated
2026-09-10
AI Q&A
2026-09-10
EPSS Evaluated
N/A
NVD
CVE-2026-65638
EUVD
EUVD-2026-75595

Affected Vendors & Products

Showing 6 associated CPEs
Vendor Product Version / Range
configserver configserver_security_and_firewall From 14.00 (inc) to 16.29 (inc)
configserver configserver_security_and_firewall 16.30
webpros configserver_security_and_firewall From 14.00 (inc) to 16.29 (inc)
webpros configserver_security_and_firewall 16.30
configserver configserver_security_firewall to 16.30 (inc)
webpros configserver_security_firewall to 16.30 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
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

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Executive Summary

This vulnerability is a shell command injection flaw in ConfigServer Security & Firewall (CSF) caused by improper escaping of a request URL. An unauthenticated remote attacker can exploit it to execute arbitrary commands as the CSF service account.

Detection Guidance

To detect this vulnerability, check the installed version of ConfigServer Security & Firewall (CSF) by running 'csf -v' or checking the version in the CSF configuration file. If the version is between 14.00 and 16.29, the system is vulnerable. Additionally, verify if the MESSENGER service is enabled by inspecting the CSF configuration file at /etc/csf/csf.conf for the MESSENGER option.

Impact Analysis

An attacker could gain control over the CSF service account, potentially leading to unauthorized system access, data manipulation, or further network compromise. The impact depends on the service account's privileges.

Mitigation Strategies
  • Update CSF to version 16.30 or later using the appropriate command for your system: 'yum clean all' followed by '/scripts/update-packages' for CentOS 7/CloudLinux 7, 'dnf clean all' followed by '/scripts/update-packages' for AlmaLinux/CloudLinux 8/9/10, or 'apt update' followed by '/scripts/update-packages' for Ubuntu.
  • If updating is not possible, disable the MESSENGER service by editing /etc/csf/csf.conf, setting MESSENGER to 0, saving the file, and restarting CSF and LFD services with 'systemctl restart csf lfd'.

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