CVEvulnerability

CVE-2026-42376

9.8 CRITICAL Published 2026-05-04 Modified 2026-10-26 Official page ↗
Status
Analyzed
Published
2026-05-04
Last modified
2026-10-26
Assigner
33c584b5-0579-4c06-b2a0-8d8329fcab9c
CVSS 3.1 (33c584b5-0579-4c06-b2a0-8d8329fcab9c)
9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weaknesses
CWE-798

Description

D-Link DIR-456U Hardware Revision A1 (End-of-Life, EOL) contains a hardcoded telnet backdoor. The device starts a telnet daemon at boot via /etc/init0.d/S80telnetd.sh with the username "Alphanetworks" and the static password "whdrv01_dlob_dir456U" read from /etc/config/image_sign. The custom telnetd binary accepts a -u user:password flag, and the custom login binary uses strcmp() to validate credentials. Successful authentication grants an unauthenticated attacker on the local network a root shell with full administrative control. The device has reached End-of-Life (EOL) and will not receive patches.

Affected configurations

• dlink dir-456u firmware

Related

Weakness · CWE (1)

  • CWE-798 Use of Hard-coded Credentials weakness

References