CVE-2026-5212 is a stack-based buffer overflow vulnerability affecting a range of D-Link DNS devices up to firmware version 20260205. The vulnerability resides in the Webdav_Upload_File function within /cgi-bin/webdav_mgr.cgi, where manipulation of the f_file argument leads to a buffer overflow condition. This flaw can be exploited remotely without authentication or user interaction, potentially allowing an attacker to execute arbitrary code or cause denial of service. The vulnerability has been publicly disclosed, increasing the risk of exploitation. No vendor advisory or patch information is currently available, and the affected devices are not cloud services.

Successful exploitation of this vulnerability could allow remote attackers to execute arbitrary code or cause a denial of service on affected D-Link DNS devices. The vulnerability is exploitable over the network without authentication or user interaction, increasing its risk. The public disclosure of the exploit code further elevates the threat level. The CVSS 4.0 score of 8.7 reflects high impact on confidentiality, integrity, and availability.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. In the absence of an official fix, consider disabling or restricting access to the Webdav service or the /cgi-bin/webdav_mgr.cgi endpoint to trusted networks only, if possible. Monitor vendor channels for updates and apply official patches once available.