CVE-2024-23828: Nginxui Nginx UI RCE Vulnerability

CVE-2024-23828 Overview

CVE-2024-23828 is an authenticated command execution vulnerability in Nginx-UI, a web interface for managing Nginx configurations. The flaw allows authenticated attackers to inject arbitrary operating system commands via a Carriage Return Line Feed (CRLF) injection attack when modifying the test_config_cmd or start_cmd configuration values. This issue exists because of an incomplete fix for CVE-2024-22197 and CVE-2024-22198. The vulnerability is tracked under [CWE-74] (Improper Neutralization of Special Elements in Output) and was patched in version 2.0.0.beta.12.

Critical Impact
Authenticated attackers can execute arbitrary operating system commands on the host running Nginx-UI, resulting in full compromise of confidentiality, integrity, and availability.

Affected Products

Nginx-UI versions prior to 2.0.0.beta.12
Nginx-UI 2.0.0 beta1 through beta11 (including patch releases)
Deployments exposing the Nginx-UI management interface to authenticated users

Discovery Timeline

2024-01-29 - CVE-2024-23828 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-23828

Vulnerability Analysis

Nginx-UI exposes configuration endpoints that let authenticated users set values for test_config_cmd and start_cmd. These values are passed to a system command execution path. Prior fixes for CVE-2024-22197 and CVE-2024-22198 attempted to restrict command content but did not neutralize CRLF sequences.

An attacker with valid credentials can embed a \r\n sequence followed by an arbitrary command into these configuration fields. When the application processes the multi-line input, the injected line is interpreted as an additional command. The result is arbitrary command execution in the security context of the Nginx-UI process.

Root Cause

The root cause is incomplete input sanitization on the test_config_cmd and start_cmd parameters. The previous patches for CVE-2024-22197 and CVE-2024-22198 blocked certain characters but failed to strip or reject carriage return and line feed control characters. This left an injection primitive that adversaries can use to break out of the intended single-command boundary.

Attack Vector

Exploitation requires an authenticated session with permission to modify Nginx-UI configuration. The attacker submits a crafted value containing CRLF characters through the configuration API or user interface. Once the modified test_config_cmd or start_cmd is invoked by the application, the injected command runs on the underlying host.

Because Nginx-UI typically runs with sufficient privileges to control Nginx service state, successful exploitation often yields high-privilege code execution. This vector maps directly to remote command injection via a network-reachable management interface.

Detection Methods for CVE-2024-23828

Indicators of Compromise

Unexpected modifications to the Nginx-UI configuration file containing embedded newline characters within test_config_cmd or start_cmd values.
Child processes spawned by the Nginx-UI binary that do not match legitimate Nginx test or start commands.
Outbound network connections from the Nginx-UI host process to unfamiliar destinations shortly after configuration changes.
Audit log entries showing configuration API calls updating command fields from non-administrative accounts.

Detection Strategies

Inspect Nginx-UI configuration files and API request bodies for the presence of \r, \n, or %0A/%0D sequences inside command-related fields.
Monitor process creation events where the parent process is nginx-ui and the child process is a shell, interpreter, or reconnaissance utility such as sh, bash, curl, or wget.
Correlate authentication events with subsequent configuration changes to identify accounts abusing legitimate access.

Monitoring Recommendations

Enable verbose audit logging on Nginx-UI and forward events to a centralized log platform for retention and analysis.
Alert on any modification to test_config_cmd or start_cmd values in production environments.
Baseline expected child processes of the Nginx-UI service and alert on deviations.

How to Mitigate CVE-2024-23828

Immediate Actions Required

Upgrade Nginx-UI to version 2.0.0.beta.12 or later on all affected hosts.
Rotate all Nginx-UI administrative credentials and API tokens that existed before the upgrade.
Review recent configuration changes and audit logs for evidence of CRLF-based command injection attempts.
Restrict network access to the Nginx-UI management interface to trusted administrative networks only.

Patch Information

The vendor released a fix in Nginx-UI 2.0.0.beta.12 that neutralizes CRLF sequences in the affected command fields. Refer to the GitHub Security Advisory GHSA-qcjq-7f7v-pvc8 for advisory details and upgrade guidance.

Workarounds

Place the Nginx-UI interface behind a reverse proxy or VPN that enforces additional authentication and IP allowlisting.
Limit which user accounts have permission to modify command-related configuration values.
Run Nginx-UI under a dedicated, low-privilege service account with restricted filesystem and network capabilities.
Monitor and alert on any changes to the Nginx-UI configuration file until the patched version is deployed.

bash

# Example: restrict management interface access via firewall
sudo ufw allow from 10.0.0.0/24 to any port 9000 proto tcp
sudo ufw deny 9000/tcp