Executive brief
D-Link DSL-3782 is a router/DSL gateway device used to provide internet connectivity in homes and small businesses. A vulnerability in the Diagnostics web interface allows authenticated users to inject arbitrary shell commands via the address parameter, leading to full compromise of the device including credential theft, traffic interception, and persistent backdoor installation.
Technical details
The vulnerability is a command injection flaw in the /cgi-bin/New_GUI/Set/Diagnostics.asp endpoint. The Addr parameter, intended for ping/traceroute diagnostics, is passed unsanitized into a system() call without input validation or shell-escaping. An authenticated attacker can inject shell metacharacters (e.g., semicolons, pipes) to execute arbitrary commands with root privileges. The attack vector is network-based and requires prior authentication; exploitation has been demonstrated via proof-of-concept. The root cause is the lack of input validation and use of system() instead of safer alternatives like exec* family functions. Patches or vendor guidance are not yet publicly available.
Affected products
- D-Link DSL-3782 from 2016-07-28 firmware
Timeline
- 2026-09-15: disclosed: CVE-2026-90880 published to NVD
- 2026-07-05: other: Vulnerability discovered via autonomous dynamic analysis and confirmed via file_write_canary oracle
- 2026-08-14: other: Disclosure draft prepared for D-Link PSIRT; status marked as DRAFT for submission