Tenda HG10 HG7_HG9_HG10re_300001138_en_xpon Buffer Overflow Vulnerability

A buffer overflow vulnerability, identified as CVE-2026-6988, has been discovered in Tenda HG10 HG7_HG9_HG10re_300001138_en_xpon. The vulnerability resides within the Boa Service, specifically affecting the formRoute function located in the /boaform/formRouting file. Successful exploitation of this flaw enables a remote attacker to overwrite memory by crafting a malicious request with a manipulated nextHop argument. This can lead to arbitrary code execution on the affected device. Given the potential for remote exploitation and the availability of a published exploit, this vulnerability poses a significant threat.

Attack Chain

1. The attacker identifies a vulnerable Tenda HG10 HG7_HG9_HG10re_300001138_en_xpon device with the vulnerable Boa web service exposed.
2. The attacker crafts a malicious HTTP request targeting the /boaform/formRouting endpoint.
3. The crafted request includes a specially crafted nextHop argument, exceeding the buffer size allocated for it.
4. The Boa service processes the request without proper bounds checking on the nextHop argument.
5. The oversized nextHop argument overwrites adjacent memory regions, including critical program data or return addresses.
6. The overwritten return address redirects execution flow to attacker-controlled code.
7. The attacker executes arbitrary code on the device with the privileges of the Boa service.
8. The attacker gains control of the device, potentially leading to data exfiltration, device hijacking, or further network compromise.

Impact

Successful exploitation of CVE-2026-6988 can lead to complete compromise of the affected Tenda HG10 HG7_HG9_HG10re_300001138_en_xpon device. This may result in unauthorized access to the device’s configuration, sensitive data exposure, or the device being used as a bot in a larger attack. Given that this device is likely used in home or small business environments, a successful attack could lead to significant data breaches, financial losses, and reputational damage. The availability of a public exploit increases the likelihood of widespread exploitation.

Recommendation

• Apply available patches or firmware updates released by Tenda to address CVE-2026-6988 as soon as possible.
• Implement network segmentation to limit the exposure of Tenda devices to the internet or untrusted networks.
• Monitor web server logs for suspicious activity targeting the /boaform/formRouting endpoint to detect potential exploit attempts (webserver log source).
• Deploy the Sigma rule “Detect Tenda HG10 Buffer Overflow Attempt” to identify malicious HTTP requests exploiting the nextHop argument (Sigma rule).
• Implement rate limiting on the /boaform/formRouting endpoint to mitigate potential brute-force exploitation attempts.