CVE-2026-1143
Published: 19 January 2026
Summary
CVE-2026-1143 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Totolink A3700R Firmware. Its CVSS base score is 7.4 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 46.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).
Deeper analysis
CVE-2026-1143 is a buffer overflow vulnerability affecting the TOTOLINK A3700R router on firmware version 9.1.2u.5822_B20200513. The issue lies in the setWiFiEasyGuestCfg function within the /cgi-bin/cstecgi.cgi file, where manipulation of the ssid argument triggers the overflow. Published on 2026-01-19, it is associated with CWEs-119 and CWE-120.
The vulnerability carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating network-based remote exploitation with low complexity and low privileges required, such as an authenticated user, and no user interaction needed. Successful exploitation can result in high impacts to confidentiality, integrity, and availability, potentially allowing remote code execution. A public exploit is available for attacks.
Advisories and details are available at https://lavender-bicycle-a5a.notion.site/TOTOLINK-A3700R-setWiFiEasyGuestCfg-2e353a41781f8057a244ead07d5eaaff?source=copy_link, https://vuldb.com/?ctiid.341735, https://vuldb.com/?id.341735, and https://vuldb.com/?submit.735502, with the vendor site at https://www.totolink.net/.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-3236
Vulnerability details
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…
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made available to the public and could be used for attacks.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The vulnerability is a buffer overflow in a public-facing router web interface (CGI script) enabling remote code execution with low privileges, directly mapping to exploitation of public-facing applications.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly remediates the buffer overflow flaw in the setWiFiEasyGuestCfg function by identifying, reporting, and correcting the vulnerability through patching or firmware updates.
Enforces validation of the ssid argument in the cgi-bin script to prevent buffer overflows from malicious input manipulation.
Implements memory protections such as DEP or stack canaries to mitigate exploitation of the buffer overflow for remote code execution.