CVE-2026-1143
Buffer Overflow in TOTOLINK A3700R WiFi Guest Config CGI
Publication date: 2026-01-19
Last updated on: 2026-01-19
Assigner: VulDB
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| totolink | a3700r | 9.1.2u.5822_b20200513 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-119 | The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data. |
| CWE-120 | The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2026-1143 is a buffer overflow vulnerability in the TOTOLINK A3700R router firmware version 9.1.2u.5822_B20200513. It occurs in the setWiFiEasyGuestCfg function of the /cgi-bin/cstecgi.cgi script when processing the 'ssid' argument. The firmware improperly handles the input by decoding the SSID and copying it to a stack buffer without checking the input size, which can overflow the buffer. This flaw can be exploited remotely without authentication and may allow an attacker to execute arbitrary code or cause a denial of service. [1, 2]
How can this vulnerability impact me? :
This vulnerability can impact you by compromising the confidentiality, integrity, and availability of the affected TOTOLINK A3700R router. An attacker exploiting this buffer overflow can remotely execute arbitrary code or cause the device to crash (denial of service). Since the exploit is publicly available and requires no authentication, the risk of attack is high. This could lead to unauthorized control over the router, disruption of network services, or further attacks on connected devices. [1, 2]
How can this vulnerability be detected on my network or system? Can you suggest some commands?
Detection can be performed by monitoring for suspicious HTTP requests targeting the endpoint /cgi-bin/cstecgi.cgi with the setWiFiEasyGuestCfg function, especially those manipulating the 'ssid' parameter with unusually long or malformed input that could trigger a buffer overflow. Network intrusion detection systems (NIDS) can be configured to alert on such patterns. Additionally, inspecting router logs for abnormal access or crashes related to this CGI script may help. Specific commands depend on the environment, but using tools like curl to test the endpoint with crafted 'ssid' parameters or using network monitoring tools (e.g., tcpdump, Wireshark) to capture suspicious traffic can be useful. [1, 2]
What immediate steps should I take to mitigate this vulnerability?
Immediate mitigation steps include replacing the affected TOTOLINK A3700R device with a non-vulnerable alternative, as no known mitigations or patches currently exist. Restricting remote access to the router's management interface and disabling the vulnerable CGI endpoint if possible may reduce exposure. Monitoring for exploit attempts and applying network-level protections such as firewall rules to block suspicious traffic targeting /cgi-bin/cstecgi.cgi can also help. [2]