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Vulnerability record · CVE-2026-42374 · published 4 May 2026

CVE-2026-42374: Dlink dir-600l firmware hard-coded credentials vulnerability

Dlink · Dir 600l Firmware

D-Link DIR-600L Hardware Revision B1 (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 "wrgn61_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.

8.8 CVSS 3.1 High EPSS 0.98% · top 39.4% CWE-798 · Hard-coded credentials
8.8CVSS 3.1 base score
0.98%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

D-Link DIR-600L Hardware Revision B1 (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 "wrgn61_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:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://www.securin.io/zero-day/cve-2026-42374-hardcoded-telnet-backdoor-in-d-link-dir-600l-b1-end-of-life- ExploitThird Party Advisory
https://www.securin.io/zero-day/cve-2026-42374-hardcoded-telnet-backdoor-in-d-link-dir-600l-b1-end-of-life- ExploitThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-42374), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.