CVE-2025-4997: H3C Router Denial of Service Vulnerability

CVE-2025-4997 is a denial of service vulnerability in H3C R2+ProG routers affecting multiple functions in the HTTP POST request handler. Attackers can exploit this remotely to disrupt service availability. This post covers technical details, affected versions, impact assessment, and mitigation strategies.

CVE-2025-4997 Overview

CVE-2025-4997 affects H3C R2+ProG routers up to firmware version 200R004. The vulnerability resides in the HTTP POST request handler within /goform/aspForm, specifically in the functions UpdateWanParams, AddMacList, EditMacList, AddWlanMacList, EditWlanMacList, Edit_BasicSSID, Edit_GuestSSIDFor2P4G, Edit_BasicSSID_5G, and SetAPInfoById. Manipulation of the param argument leads to a denial-of-service condition. The flaw is remotely exploitable and the exploit has been publicly disclosed. The vendor was contacted prior to disclosure but did not respond.

Critical Impact
Remote attackers with low privileges can crash the router's HTTP service, interrupting network availability across all connected clients.

Affected Products

H3C R2+ProG router firmware up to 200R004
HTTP POST request handler component in /goform/aspForm
WAN and WLAN management interfaces exposed through the affected goform endpoints

Discovery Timeline

2025-05-20 - CVE-2025-4997 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-4997

Vulnerability Analysis

The issue is an improper resource shutdown or release condition classified under [CWE-404]. The affected goform endpoint processes HTTP POST requests containing a param value used across multiple router management functions. When crafted input reaches these handlers, the router fails to properly release or manage resources, leading to a denial-of-service state. The vulnerability requires network access and low-level authentication, but no user interaction. Successful exploitation impacts availability without affecting confidentiality or integrity.

Root Cause

The root cause is improper resource handling in the shared HTTP POST request dispatcher for /goform/aspForm. Multiple management functions read the param argument without adequate validation or cleanup logic. When the argument is manipulated, the handler enters an error path that fails to release allocated resources or terminates the web service abnormally.

Attack Vector

An attacker with low-privileged access to the router's web management interface sends a crafted HTTP POST request to /goform/aspForm. The request targets one of the vulnerable functions such as UpdateWanParams or SetAPInfoById with a malformed param value. Processing the request triggers the resource-handling defect and disrupts the HTTP service. The attack can be launched remotely if the management interface is reachable over the network. See the public disclosure on GitHub and the VulDB entry for additional technical detail.

Detection Methods for CVE-2025-4997

Indicators of Compromise

Unexpected restarts or crashes of the router's web management service
HTTP POST requests to /goform/aspForm referencing functions such as UpdateWanParams, AddMacList, or SetAPInfoById with unusual param values
Loss of connectivity or repeated reboot cycles on H3C R2+ProG devices running firmware 200R004 or earlier

Detection Strategies

Inspect web server access logs for anomalous POST bodies targeting /goform/aspForm with malformed or oversized param arguments
Correlate router web-service crash events with prior inbound HTTP POST activity from external or untrusted internal sources
Alert on repeated failed or truncated requests to the affected goform functions within short time windows

Monitoring Recommendations

Monitor network telemetry for scans probing router management interfaces on default HTTP/HTTPS ports
Track device uptime and service availability metrics for H3C routers to detect denial-of-service patterns
Forward router syslog and web-service logs into a centralized analytics platform for long-term retention and correlation

How to Mitigate CVE-2025-4997

Immediate Actions Required

Restrict access to the router's web management interface to trusted management VLANs or specific administrative IP addresses
Disable remote WAN-side management on affected H3C R2+ProG devices
Rotate administrative credentials to reduce the pool of low-privilege accounts that could trigger the vulnerable handler
Inventory H3C R2+ProG devices running firmware up to 200R004 and prioritize them for compensating controls

Patch Information

As of the last NVD update on 2026-06-17, no vendor patch is publicly documented. The vendor did not respond to the coordinated disclosure attempt. Administrators should monitor H3C security bulletins and the referenced VulDB entry for future advisories and firmware releases.

Workarounds

Place affected routers behind an upstream firewall that filters unsolicited HTTP POST traffic to the management interface
Enforce access control lists (ACLs) that permit management traffic only from designated administrator hosts
Segment the router management plane from user and guest networks to reduce exposure to low-privileged internal actors
Disable unused WLAN and SSID management features exposed through the affected goform functions where feasible

bash

# Example ACL restricting router management interface access
access-list 10 permit 10.0.0.0 0.0.0.255
access-list 10 deny any
line vty 0 4
 access-class 10 in