CVE-2026-1596 is a command injection vulnerability identified in the D-Link DWR-M961 router firmware version 1.1.47. The vulnerability resides in the function sub_419920 within the /boafrm/formLtefotaUpgradeQuectel file, specifically in the handling of the fota_url parameter. This parameter is used in a manner that allows an attacker to inject arbitrary commands into the system shell, leading to remote code execution. The attack vector is network-based (AV:N), requiring no user interaction (UI:N), and no authentication (AT:N), but does require low privileges (PR:L), indicating that an attacker with minimal access can exploit this flaw. The vulnerability impacts confidentiality, integrity, and availability, as arbitrary commands can compromise device operation and potentially the broader network. The CVSS 4.0 score is 5.3 (medium), reflecting the moderate ease of exploitation and impact. Although no known exploits are currently active in the wild, a public exploit has been published, increasing the likelihood of exploitation attempts. The affected product, D-Link DWR-M961, is a 4G LTE router commonly used in small to medium enterprise and residential environments. The lack of an official patch at the time of reporting necessitates interim mitigations. The vulnerability could be leveraged to disrupt network connectivity, exfiltrate sensitive data, or pivot to other internal systems. Attackers may exploit this flaw to gain persistent access or launch denial-of-service attacks. The vulnerability is particularly concerning for organizations relying on this device for critical connectivity or as part of their network infrastructure.

For European organizations, exploitation of CVE-2026-1596 could lead to significant operational disruptions, especially for those relying on the D-Link DWR-M961 router for internet connectivity or as part of their network infrastructure. Successful command injection could allow attackers to execute arbitrary commands, potentially leading to device compromise, network outages, or unauthorized access to internal systems. This could impact confidentiality by exposing sensitive data traversing the network, integrity by altering device configurations or firmware, and availability by causing device malfunctions or denial-of-service conditions. Given the remote exploitability without user interaction or authentication, attackers could target vulnerable devices en masse, increasing the risk of widespread disruption. Organizations in sectors such as telecommunications, small and medium enterprises, and critical infrastructure that utilize these routers may face increased risk. Additionally, compromised devices could be used as footholds for further lateral movement or as part of botnets, amplifying the threat landscape. The medium severity score suggests a moderate but non-negligible risk, warranting timely mitigation to prevent exploitation.

1. Monitor D-Link’s official channels for firmware updates addressing CVE-2026-1596 and apply patches immediately upon release. 2. Until patches are available, restrict access to the router’s management interfaces, especially the /boafrm/formLtefotaUpgradeQuectel endpoint, by implementing network-level controls such as firewall rules or access control lists (ACLs) to limit exposure to trusted IP addresses only. 3. Disable remote management features if not required to reduce the attack surface. 4. Employ network intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics capable of detecting attempts to exploit command injection patterns targeting the fota_url parameter. 5. Conduct regular security audits and vulnerability scans on network devices to identify the presence of vulnerable firmware versions. 6. Segment networks to isolate critical systems from devices that may be vulnerable to exploitation. 7. Educate network administrators on the risks associated with this vulnerability and ensure they follow secure configuration best practices. 8. Consider deploying endpoint detection and response (EDR) solutions to identify anomalous behavior indicative of compromise stemming from this vulnerability.