CVE-2026-3943: H3C ACG1000-AK230 RCE Vulnerability

CVE-2026-3943 Overview

A command injection vulnerability has been discovered in H3C ACG1000-AK230 network devices running firmware versions up to 20260227. This vulnerability exists in the web management interface, specifically affecting the /webui/?aaa_portal_auth_local_submit endpoint. An attacker can manipulate the suffix argument to inject and execute arbitrary commands on the underlying system. The attack can be launched remotely without authentication, making it a significant security concern for organizations using these devices.

Critical Impact

Remote attackers can exploit this command injection vulnerability to execute arbitrary commands on H3C ACG1000-AK230 devices, potentially leading to complete device compromise, network reconnaissance, and lateral movement within enterprise environments.

Affected Products

• H3C ACG1000-AK230 firmware versions up to 20260227
• H3C ACG1000-AK230 web management interface (/webui/?aaa_portal_auth_local_submit)

Discovery Timeline

• 2026-03-11 - CVE-2026-3943 published to NVD
• 2026-03-12 - Last updated in NVD database

Technical Details for CVE-2026-3943

Vulnerability Analysis

This vulnerability is classified under CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component), commonly referred to as injection vulnerabilities. The H3C ACG1000-AK230 network gateway device fails to properly sanitize user-supplied input in the suffix parameter before passing it to system command execution functions.

The vulnerability is network-accessible, requiring no authentication or user interaction to exploit. An attacker with network access to the device's web management interface can craft malicious requests that inject operating system commands through the vulnerable parameter. The exploit has been publicly disclosed, increasing the risk of active exploitation in the wild.

The vendor, H3C, has acknowledged the issue and is currently investigating and developing remediation measures.

Root Cause

The root cause of this vulnerability is improper input validation and sanitization in the web application's handling of the suffix parameter within the portal authentication functionality. The application directly incorporates user-supplied input into system commands without adequate filtering or escaping of special characters, allowing attackers to break out of the intended command context and execute arbitrary commands.

Attack Vector

The attack vector is network-based, targeting the web management interface of vulnerable H3C ACG1000-AK230 devices. An attacker can send specially crafted HTTP requests to the /webui/?aaa_portal_auth_local_submit endpoint with malicious payloads in the suffix parameter.

The exploitation flow involves:

1. Identifying an exposed H3C ACG1000-AK230 device with the web management interface accessible
2. Crafting a malicious HTTP request targeting the vulnerable endpoint
3. Injecting command injection payloads through the suffix parameter
4. Achieving command execution on the underlying operating system with the privileges of the web service

Technical details and proof-of-concept information have been documented in the GitHub CVE Issue Discussion and tracked by VulDB #350353.

Detection Methods for CVE-2026-3943

Indicators of Compromise

• Unexpected or malformed HTTP requests to /webui/?aaa_portal_auth_local_submit containing shell metacharacters in the suffix parameter
• Unusual process execution originating from the web server process on H3C ACG1000-AK230 devices
• Anomalous outbound connections from network gateway devices to unknown external hosts
• Evidence of reconnaissance commands or data exfiltration activity from gateway devices

Detection Strategies

• Deploy web application firewall (WAF) rules to detect and block command injection patterns in requests to H3C device web interfaces
• Implement network intrusion detection signatures for HTTP traffic containing common command injection payloads targeting the vulnerable endpoint
• Monitor authentication logs and web server access logs on H3C ACG1000-AK230 devices for suspicious request patterns
• Enable deep packet inspection for traffic destined to network gateway management interfaces

Monitoring Recommendations

• Configure SIEM alerts for HTTP requests containing shell metacharacters (;, |, &, `, $()) targeting H3C device management interfaces
• Establish baseline behavior for H3C ACG1000-AK230 devices and alert on deviations in process execution or network activity
• Implement network segmentation monitoring to detect lateral movement from compromised gateway devices
• Review access logs regularly for requests to the /webui/?aaa_portal_auth_local_submit endpoint

How to Mitigate CVE-2026-3943

Immediate Actions Required

• Restrict network access to H3C ACG1000-AK230 web management interfaces using firewall rules or access control lists
• Place management interfaces on isolated management VLANs accessible only to authorized administrators
• Monitor H3C security advisories for official patches and updates
• Implement network-based intrusion prevention to block known command injection attack patterns

Patch Information

The vendor H3C is currently investigating and remediating this issue. Organizations should monitor official H3C security communications and apply patches immediately when released. Check the VulDB entry for the latest patch status and vendor response information.

Workarounds

• Disable or restrict access to the web management interface if not required for operations
• Implement IP-based access controls to limit management interface access to trusted administrator workstations only
• Deploy a reverse proxy with input validation capabilities in front of the management interface
• Enable additional logging on the device to facilitate detection of exploitation attempts

# Example: Restrict management interface access via firewall (adjust for your environment)
# Block external access to H3C management interface
iptables -A INPUT -p tcp --dport 80 -s ! 10.0.0.0/8 -j DROP
iptables -A INPUT -p tcp --dport 443 -s ! 10.0.0.0/8 -j DROP

# Allow only specific management hosts
iptables -A INPUT -p tcp --dport 80 -s 10.1.1.100 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 10.1.1.100 -j ACCEPT