CVE-2026-73673

Netis NC63 router firmware V3.0.0.3327 contains an unauthenticated firmware update vulnerability that allows unauthenticated attackers to submit unsigned firmware images by exploiting a missing authentication enforcement flaw in the Boa web server and netis.cgi CGI dispatcher. Attackers can send a multipart POST request to /cgi-bin/upload_fw.cgi without a valid session cookie, bypassing authentication because Boa grants access to any path containing '.cgi' regardless of cookie validation, and netis.cgi reads but does not enforce the authentication state before invoking the firmware update handler, which accepts images validated only by a forgeable additive checksum and static product strings rather than a cryptographic signature, potentially enabling persistent router compromise.

An unauthenticated attacker can install malicious firmware on the router, potentially leading to network traffic interception, data theft, and use of the router as part of a botnet. Users may lose control over their device.

Upgrade the Netis NC63 router firmware to a patched version if available. Also restrict access to the router's administrative panel to trusted networks only.