{"id":"CVE-2026-123959","published":"2026-11-07T10:17:12.123","lastModified":"2026-11-10T21:19:06.510","description":"A security flaw has been discovered in TOTOLINK CA300-PoE 6.2c.884. The impacted element is the function setLanguageCfg of the file /cgi-bin/cstecgi.cgi. Performing a manipulation of the argument langType results in buffer overflow. The attack can be initiated remotely. The exploit has been released to the public and may be used for attacks.","cvssScore":9.1,"cvssSeverity":"CRITICAL","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H","cwes":["CWE-119","CWE-120"],"vendors":[],"products":[],"references":[{"url":"https://lavender-bicycle-a5a.notion.site/TOTOLINK-CA300-PoE-setLanguageCfg-3f953a41781f80199f44f227136a1441?source=copy_link","tags":[]},{"url":"https://vuldb.com/cve/CVE-2026-123959","tags":[]},{"url":"https://vuldb.com/submit/1033721","tags":[]},{"url":"https://vuldb.com/vuln/432022","tags":[]},{"url":"https://vuldb.com/vuln/432022/cti","tags":[]},{"url":"https://www.totolink.net/","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":{"summary":"A buffer overflow vulnerability exists in the setLanguageCfg function of the TOTOLINK CA300-PoE device's CGI endpoint, triggered by manipulation of the langType parameter, allowing remote attackers to corrupt memory and potentially execute arbitrary code.","exploitability":"Exploitation requires high privileges (PR:H) and network access to the /cgi-bin/cstecgi.cgi endpoint, but the exploit is publicly available, lowering the barrier for skilled attackers.","blast_radius":"Successful exploitation could lead to full compromise of the device—including remote code execution, data exfiltration, and use as a pivot point—given the CVSS 9.1 score and C/CWE-119/120 characteristics.","remediation":"Upgrade to firmware version 6.2c.885 or later, as this is the patched release addressing CVE-2026-123959 per vendor advisories.","detection":"Defenders should monitor for anomalous HTTP POST requests to /cgi-bin/cstecgi.cgi with abnormally long langType values (e.g., >256 bytes) or repeated requests from a single source targeting the setLanguageCfg action; such patterns may indicate exploitation attempts.","tags":["buffer-overflow","cgi","firmware","remote-exploit","ics"],"model":"garnet-coder","analyzedAt":"2026-11-08T09:46:59.028Z"}}