CVE-2026-42375: D-Link DIR-600L A1 Hardcoded Telnet Backdoor Credentials
D-Link DIR-600L Hardware Revision A1 (End-of-Life) contains a hardcoded telnet backdoor. The device starts a telnet daemon at boot via /bin/telnetd.sh with the username "Alphanetworks" and the static password "wrgn35dlwbrdir600l" read from /etc/alphaconfig/imagesign. 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 Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-42375?
CVE-2026-42375 is rated as a critical vulnerability due to the presence of hardcoded telnet backdoor credentials.
How do I fix CVE-2026-42375?
To fix CVE-2026-42375, users should stop using the D-Link DIR-600L A1 device due to its end-of-life status and inherent security risks.
What devices are affected by CVE-2026-42375?
CVE-2026-42375 affects the D-Link DIR-600L hardware revision A1.
What are the default credentials associated with CVE-2026-42375?
The default credentials for CVE-2026-42375 are the username 'Alphanetworks' and the password 'wrgn35_dlwbr_dir600l'.
Is there a patch available for CVE-2026-42375?
There is no patch available for CVE-2026-42375, as the device is considered end-of-life.