CVE-2026-1143: TOTOLINK A3700R cstecgi.cgi setWiFiEasyGuestCfg buffer overflow

Vulnerability summary

CVE-2026-1143 is a high (CVSS 9.0) vulnerability in totolink a3700r_firmware. EPSS estimates a 0.76% chance of exploitation in the next 30 days, higher than 54.8% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 19-01-2026
   PublishedVulnerability first disclosed.
2. 23-02-2026
   Last modifiedVulnerability information updated.

Description

A weakness has been identified in TOTOLINK A3700R 9.1.2u.5822_B20200513. This affects the function setWiFiEasyGuestCfg of the file /cgi-bin/cstecgi.cgi. Executing a manipulation of the argument ssid can lead to buffer overflow. The attack may be launched remotely. The exploit has been made available to the public and could be used for attacks.

• CWE-119Improper Restriction of Operations within the Bounds of a Memory BufferThe 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-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')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.