Executive Summary

CVE-2026-4318 is a critical buffer overflow vulnerability in the UTT HiPER 810G router firmware versions up to 1.7.7-171114. It occurs in the function strcpy within the file /goform/formApLbConfig, specifically involving the argument loadBalanceNameOld.

The vulnerability arises because the code copies data from the loadBalanceNameOld parameter into a buffer without proper bounds checking, using unsafe functions like strcpy and strcat. This allows an attacker to overflow the buffer by sending an excessively long string.

The attack can be initiated remotely via an HTTP POST request to the endpoint /goform/formApLbConfig, requiring Digest authentication with administrative credentials.

Useful 0 Not Useful 0

Impact Analysis

This vulnerability can impact the confidentiality, integrity, and availability of the affected device.

• An attacker can cause a buffer overflow that may lead to denial of service (DoS), crashing the device or disrupting its normal operation.
• Potentially, other malicious effects could be exploited through this overflow, although specific remote code execution is not explicitly confirmed.

The attack complexity is low, and a proof-of-concept exploit is publicly available, increasing the risk of exploitation.

Useful 0 Not Useful 0

Compliance Impact

I don't know

Useful 0 Not Useful 0

Detection Guidance

[{'type': 'paragraph', 'content': 'This vulnerability can be detected by monitoring HTTP POST requests to the endpoint `/goform/formApLbConfig` on the UTT HiPER 810G router. Specifically, look for requests where the parameter `loadBalanceNameOld` contains an excessively long string, which is used to trigger the buffer overflow.'}, {'type': 'paragraph', 'content': 'Detection can also involve checking for authentication attempts using Digest authentication with administrative credentials, as the exploit requires such authentication.'}, {'type': 'paragraph', 'content': 'A proof-of-concept exploit involves sending a crafted HTTP POST request with a long `loadBalanceNameOld` parameter. Network monitoring tools or intrusion detection systems (IDS) can be configured to alert on unusually long values in this parameter or on POST requests to this specific endpoint.'}, {'type': 'paragraph', 'content': 'Example command using curl to test the vulnerability (requires valid admin credentials):'}, {'type': 'list_item', 'content': 'curl -X POST -u admin:password --digest -d "Action=add&loadBalanceNameOld=$(python3 -c \'print("A"*1000)\')" http://<router-ip>/goform/formApLbConfig'}, {'type': 'paragraph', 'content': 'Replace `<router-ip>`, `admin`, and `password` with the appropriate values. This command sends a very long string in the `loadBalanceNameOld` parameter to test for buffer overflow behavior.'}] [1]

Useful 0 Not Useful 0

Mitigation Strategies

[{'type': 'paragraph', 'content': 'Currently, there are no known countermeasures or mitigations available for this vulnerability.'}, {'type': 'paragraph', 'content': 'The recommended immediate step is to replace the affected UTT HiPER 810G device or firmware version (up to 1.7.7-171114) with a secure alternative that is not vulnerable.'}, {'type': 'paragraph', 'content': "Additionally, restrict access to the device's management interface to trusted networks and users only, and monitor for suspicious activity targeting the `/goform/formApLbConfig` endpoint."}] [2]

Useful 0 Not Useful 0