CVE-2025-6091: H3C GR-3000AX Buffer Overflow Vulnerability

CVE-2025-6091 Overview

CVE-2025-6091 is a buffer overflow vulnerability in the H3C GR-3000AX router running firmware version V100R007L50. The flaw resides in the UpdateWanParamsMulti and UpdateIpv6Params functions inside /routing/goform/aspForm. Manipulating the param argument triggers memory corruption classified under [CWE-119]. Attackers can exploit the issue remotely over the network with low privileges. The exploit details are public, increasing the likelihood of opportunistic abuse. The vendor has acknowledged the issue but assesses the risk as low and does not plan immediate remediation, leaving deployed devices exposed.

Critical Impact
Remote attackers with low-privileged access can trigger a buffer overflow in the router's web management interface, potentially leading to arbitrary code execution or denial of service on the affected device.

Affected Products

H3C GR-3000AX router
Firmware version V100R007L50
Web management component /routing/goform/aspForm

Discovery Timeline

2025-06-15 - CVE-2025-6091 published to NVD
2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-6091

Vulnerability Analysis

The vulnerability exists in the H3C GR-3000AX web management interface, specifically in the aspForm handler at /routing/goform/aspForm. The functions UpdateWanParamsMulti and UpdateIpv6Params process the param argument without proper bounds checking on the supplied input length. Submitting an oversized value writes beyond the allocated buffer, corrupting adjacent memory regions. This corruption can overwrite return addresses, function pointers, or critical control structures within the embedded HTTP service. Attackers can leverage this to crash the service or, with sufficient control over the overwritten data, redirect execution to attacker-controlled code on the device.

Root Cause

The root cause is improper restriction of operations within the bounds of a memory buffer [CWE-119]. The affected functions copy attacker-controlled param data into a fixed-size stack or heap buffer without validating the input length. This is a common pattern in embedded router firmware where C-based CGI handlers use unsafe string operations such as strcpy or sprintf.

Attack Vector

The attack vector is network-based and requires only low-level authenticated access to the router's administrative interface. An attacker reachable over HTTP/HTTPS sends a crafted POST request to /routing/goform/aspForm containing an overlong param value. Because the exploit has been publicly disclosed, unauthenticated tooling and proof-of-concept payloads referenced in the GitHub CVE Details writeup are accessible to opportunistic attackers. The Exploit Prediction Scoring System (EPSS) rates the probability of exploitation accordingly, and routers exposed to the internet face elevated risk.

Detection Methods for CVE-2025-6091

Indicators of Compromise

HTTP POST requests to /routing/goform/aspForm containing abnormally long param values
Unexpected restarts or crashes of the router's httpd or web management process
Configuration changes to WAN or IPv6 settings that do not correlate with administrator activity
Outbound connections from the router to unfamiliar hosts following suspicious admin-interface traffic

Detection Strategies

Inspect web server access logs on the router for requests targeting UpdateWanParamsMulti or UpdateIpv6Params with oversized parameters
Deploy network intrusion detection signatures that flag POST bodies exceeding expected length thresholds for /routing/goform/aspForm
Correlate management-interface traffic with device reboots or service restarts to identify exploitation attempts

Monitoring Recommendations

Forward router syslog and HTTP access logs to a centralized SIEM for retention and anomaly detection
Alert on access to the router's web management interface from unexpected source IP ranges
Monitor for repeated authentication followed by malformed administrative requests, which suggests scripted exploitation

How to Mitigate CVE-2025-6091

Immediate Actions Required

Restrict access to the router's web management interface so it is reachable only from trusted management networks
Disable remote (WAN-side) administration on the GR-3000AX until a fix is available
Rotate administrative credentials and enforce strong, unique passwords to reduce the impact of low-privilege exploitation
Place affected devices behind a network firewall or VPN concentrator that filters inbound HTTP/HTTPS traffic

Patch Information

H3C has confirmed the vulnerability but has not committed to a remediation timeline, classifying the risk as low. No vendor patch is currently available. Operators should track vendor advisories and consult the VulDB #312558 entry for updates. Until a firmware update is released, mitigation depends on network-level controls.

Workarounds

Block external access to /routing/goform/aspForm at the perimeter firewall
Limit administrative HTTP/HTTPS access to a hardened jump host or management VLAN
Replace internet-facing GR-3000AX devices running V100R007L50 with alternative hardware if exposure cannot be eliminated
Apply egress filtering on the router to limit the impact of successful code execution

bash

# Example: restrict router management interface to trusted subnet using upstream firewall
iptables -A FORWARD -p tcp -d <router-ip> --dport 443 -s 10.10.0.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d <router-ip> --dport 443 -j DROP
iptables -A FORWARD -p tcp -d <router-ip> --dport 80 -j DROP