CVE-2025-3544: H3C Magic Router RCE Vulnerability

CVE-2025-3544 Overview

CVE-2025-3544 is a command injection vulnerability affecting H3C Magic series routers, including the Magic NX15, Magic NX30 Pro, Magic NX400, Magic R3010, and Magic BE18000 running firmware up to V100R014. The flaw resides in the FCGI_CheckStringIfContainsSemicolon function within the /api/wizard/getCapabilityWeb endpoint handled by the HTTP POST request handler. Attackers on the adjacent network can manipulate request parameters to inject and execute arbitrary shell commands on the device. A proof-of-concept has been publicly disclosed, increasing exposure for unpatched deployments. The vulnerability is categorized under [CWE-74] (Improper Neutralization of Special Elements in Output Used by a Downstream Component).

Critical Impact
Successful exploitation grants attackers arbitrary command execution on affected H3C Magic routers, enabling full device compromise, traffic interception, and lateral movement across the local network.

Affected Products

H3C Magic NX15, Magic NX30 Pro, Magic NX400 (firmware up to V100R014)
H3C Magic R3010 (firmware up to V100R014)
H3C Magic BE18000 (firmware up to V100R014)

Discovery Timeline

2025-04-14 - CVE-2025-3544 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-3544

Vulnerability Analysis

The vulnerability exists in the FastCGI request processing path of the router's web management interface. When a client sends an HTTP POST request to /api/wizard/getCapabilityWeb, the handler invokes FCGI_CheckStringIfContainsSemicolon to inspect user-supplied input. The function fails to properly neutralize shell metacharacters before passing input to a downstream command interpreter. Attackers craft payloads that break out of the intended parameter context and execute arbitrary operating system commands with the privileges of the web service, typically root on embedded router firmware.

Root Cause

The root cause is improper input sanitization in a downstream component [CWE-74]. Although the function name suggests it checks for semicolons, the validation logic is either bypassable or fails to account for the full range of shell metacharacters such as backticks, $(), pipes, and newlines. User-controlled data flows directly into a system command context without safe escaping or parameterization.

Attack Vector

Exploitation requires network adjacency to the target router, meaning the attacker must reach the device from the local network segment. Authentication with low privileges is required. An attacker submits a specially crafted HTTP POST body to the vulnerable endpoint, embedding shell command sequences in fields processed by the FastCGI handler. The injected commands run in the context of the router's management service. Refer to the GitHub Gist PoC Repository and VulDB #304583 for public technical details.

Detection Methods for CVE-2025-3544

Indicators of Compromise

HTTP POST requests to /api/wizard/getCapabilityWeb containing shell metacharacters such as ;, |, &, backticks, or $() in parameter values.
Unexpected child processes spawned from the router's FastCGI or httpd service.
New or modified files in writable firmware locations such as /tmp or /var following management interface access.
Outbound connections from the router to unknown external hosts shortly after management-plane activity.

Detection Strategies

Inspect web server and reverse proxy logs for POST requests targeting /api/wizard/getCapabilityWeb and parse request bodies for injection payloads.
Deploy network intrusion detection signatures that flag command injection patterns against H3C Magic management endpoints.
Correlate management interface authentications with subsequent anomalous device behavior such as configuration changes or DNS redirection.

Monitoring Recommendations

Restrict router management access to a dedicated administrative VLAN and log all authentication attempts to a centralized SIEM.
Baseline normal HTTP traffic to router management interfaces and alert on deviations in request size, frequency, or parameter content.
Monitor DHCP, DNS, and routing table changes on affected devices for signs of post-exploitation tampering.

How to Mitigate CVE-2025-3544

Immediate Actions Required

Upgrade affected H3C Magic devices to the latest firmware available from the H3C Software Download Page.
Disable remote management on the WAN interface and restrict LAN-side management access to trusted administrator hosts.
Rotate administrator credentials on all affected routers after patching to invalidate any credentials that may have been captured.
Audit device configurations for unauthorized changes to DNS servers, static routes, firewall rules, and port forwarding entries.

Patch Information

H3C has published guidance and firmware updates for the affected Magic series products. Refer to the H3C Theme Details Article and the vendor download portal for the correct firmware version for each specific model. Apply the firmware release that supersedes V100R014 for the affected product line.

Workarounds

Place vulnerable routers behind a network segment that blocks untrusted hosts from reaching the management interface on TCP ports used for HTTP administration.
Enforce strong, unique administrative credentials and disable any default or shared accounts on the device.
Use access control lists to limit source addresses permitted to reach /api/wizard/getCapabilityWeb and other management URIs until firmware can be updated.

bash

# Configuration example: restrict router management access on an upstream firewall
# Only permit the administrator workstation to reach the router web UI
iptables -A FORWARD -s 192.0.2.10 -d 192.168.1.1 -p tcp --dport 80 -j ACCEPT
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 80 -j DROP
iptables -A FORWARD -s 192.0.2.10 -d 192.168.1.1 -p tcp --dport 443 -j ACCEPT
iptables -A FORWARD -d 192.168.1.1 -p tcp --dport 443 -j DROP