CVE-2025-4440 Overview
CVE-2025-4440 is a buffer overflow vulnerability affecting the H3C GR-1800AX wireless router up to firmware version 100R008. The flaw resides in the EnableIpv6 function of the /goform/aspForm endpoint. Attackers can trigger the overflow by manipulating the param argument sent to the affected form handler. Exploitation requires access to the local (adjacent) network and low-privilege authentication. The exploit details have been publicly disclosed, increasing the risk of opportunistic attacks against exposed devices. The vulnerability is categorized under [CWE-119] Improper Restriction of Operations within the Bounds of a Memory Buffer.
Critical Impact
Successful exploitation can corrupt router memory, enabling denial of service or potential arbitrary code execution on the H3C GR-1800AX device from the local network.
Affected Products
- H3C GR-1800AX wireless router
- Firmware versions up to and including 100R008
- Devices exposing the /goform/aspForm web management interface
Discovery Timeline
- 2025-05-08 - CVE-2025-4440 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-4440
Vulnerability Analysis
The vulnerability exists in the EnableIpv6 function handled through the router's /goform/aspForm web interface. This form endpoint processes HTTP requests for administrative configuration tasks including IPv6 enablement. The handler copies attacker-supplied data from the param argument into a fixed-size buffer without adequate bounds checking. When the supplied value exceeds the destination buffer size, adjacent memory is overwritten. Depending on memory layout, this can cause the web server process to crash or allow control-flow hijacking on the embedded MIPS or ARM architecture typical of these devices. Exploitation requires network adjacency, meaning the attacker must reside on the same layer-2 network segment as the router.
Root Cause
The root cause is improper input validation in the EnableIpv6 handler within /goform/aspForm. The function lacks length verification before writing the param value into a stack or heap buffer, matching the [CWE-119] classification. Embedded router firmware frequently uses unsafe C library functions such as strcpy or sprintf in CGI-style handlers, which is the likely pattern in this component.
Attack Vector
An authenticated attacker on the adjacent network sends a crafted HTTP POST request to /goform/aspForm, invoking the EnableIpv6 action with an oversized param value. The overflow overwrites adjacent stack or heap memory, producing a denial of service or potentially executing attacker-controlled shellcode with the privileges of the web management process, which typically runs as root on consumer routers. Because the interface is exposed on the LAN, any compromised device on the same network segment can reach the vulnerable endpoint.
No verified proof-of-concept code is available in the enriched dataset. Technical write-up details are hosted at the GitHub Configuration File and referenced in VulDB #308048.
Detection Methods for CVE-2025-4440
Indicators of Compromise
- HTTP POST requests to /goform/aspForm containing abnormally long param values targeting the EnableIpv6 action.
- Unexpected crashes, reboots, or watchdog restarts of the H3C GR-1800AX web management daemon.
- New or unexplained administrative configuration changes, particularly IPv6-related settings, following suspicious LAN activity.
Detection Strategies
- Deploy network intrusion detection signatures that inspect HTTP request length and payload structure sent to /goform/aspForm.
- Baseline normal management-plane traffic to the router and alert on unusual request sizes or non-administrative source hosts issuing configuration commands.
- Correlate router syslog entries indicating process restarts with concurrent HTTP requests to the vulnerable endpoint.
Monitoring Recommendations
- Forward router syslog and web-management logs to a centralized SIEM for retention and correlation.
- Monitor DHCP and ARP tables to identify unauthorized devices joining the LAN that could reach the router's management interface.
- Alert on repeated authentication events against the router web UI from non-administrative hosts.
How to Mitigate CVE-2025-4440
Immediate Actions Required
- Restrict access to the router's web management interface to a dedicated management VLAN or specific administrative host addresses.
- Change default and shared administrative credentials to reduce the risk of low-privilege attackers reaching the vulnerable endpoint.
- Isolate untrusted devices such as guest Wi-Fi clients on a separate SSID and VLAN that cannot reach the router management interface.
Patch Information
No vendor patch or advisory URL is listed in the enriched CVE data at the time of writing. Administrators should monitor H3C's official support channels for firmware updates addressing the EnableIpv6 handler in versions later than 100R008. Until a patched firmware is released, apply the compensating controls described in the workarounds section.
Workarounds
- Disable remote management and confirm the web administration interface is not reachable from the WAN side.
- Where supported, disable IPv6 configuration from the web UI or block access to the specific /goform/aspForm path via an upstream firewall or ACL.
- Segment IoT and consumer devices away from the router management network to reduce the pool of potential attackers on the adjacent network.
- Replace end-of-life or unmaintained devices with vendor-supported models if no patch becomes available.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
