CVE-2026-42375

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 "wrgn35_dlwbr_dir600l" read from /etc/alpha_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.

CVSS v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://www.securin.io/zero-day/cve-2026-42375-hardcoded-telnet-backdoor-in-d-link-dir-600l-a1-end-of-life-	Exploit Third Party Advisory
https://www.securin.io/zero-day/cve-2026-42375-hardcoded-telnet-backdoor-in-d-link-dir-600l-a1-end-of-life-	Exploit Third Party Advisory

Configurations

Configuration 1 (hide)

AND

cpe:2.3:o:dlink:dir-600l_firmware:*:*:*:*:*:*:*:*

cpe:2.3:h:dlink:dir-600l:a1:*:*:*:*:*:*:*

History

06 May 2026, 12:17

Type	Values Removed	Values Added
First Time		Dlink dir-600l Firmware Dlink dir-600l Dlink
References	~~() https://www.securin.io/zero-day/cve-2026-42375-hardcoded-telnet-backdoor-in-d-link-dir-600l-a1-end-of-life- -~~	() https://www.securin.io/zero-day/cve-2026-42375-hardcoded-telnet-backdoor-in-d-link-dir-600l-a1-end-of-life- - Exploit, Third Party Advisory
CPE		cpe:2.3:h:dlink:dir-600l:a1:::::::* cpe:2.3:o:dlink:dir-600l_firmware::::::::

04 May 2026, 17:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-05-04 17:16

Updated : 2026-05-06 12:17

NVD link : CVE-2026-42375

Mitre link : CVE-2026-42375

CVE.ORG link : CVE-2026-42375

JSON object : View

Products Affected

dlink

dir-600l_firmware
dir-600l

CWE

CWE-798

Use of Hard-coded Credentials

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