Vulnerability Details 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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.003
EPSS Ranking 50.6%
CVSS Severity
CVSS v3 Score 9.8
References
Products affected by CVE-2026-42375
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cpe:2.3:h:dlink:dir-600l:a1
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cpe:2.3:o:dlink:dir-600l_firmware:1.00
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cpe:2.3:o:dlink:dir-600l_firmware:1.15
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cpe:2.3:o:dlink:dir-600l_firmware:1.16
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cpe:2.3:o:dlink:dir-600l_firmware:1.16wwb01
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cpe:2.3:o:dlink:dir-600l_firmware:2.00
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cpe:2.3:o:dlink:dir-600l_firmware:2.05
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cpe:2.3:o:dlink:dir-600l_firmware:2.056b06
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cpe:2.3:o:dlink:dir-600l_firmware:2.07b01