PT-2026-36835 · D Link · Dir600L

Arjun Basnet · Published 2026-04-20 · Updated 2026-05-13 · CVE-2026-42374

Positive Technologies (AI Summary)

CVSS v3.1

10

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions D-Link DIR-600L Hardware Revision B1

Description A hardcoded telnet backdoor exists where the device starts a telnet daemon at boot via the /bin/telnetd.sh script. The system uses a static username "Alphanetworks" and password "wrgn61 dlwbr dir600L" stored in /etc/alpha config/image sign. The custom telnetd binary utilizes a -u user:password flag, and the login binary employs the strcmp() function to validate credentials. An unauthenticated attacker on the local network can use these credentials to gain a root shell with full administrative control.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Using Hardcoded Credentials

Weakness Enumeration

CWE-798

CWE-259

Related Identifiers

BDU:2026-06318

CVE-2026-42374

Affected Products

Dir600L

References · 10

• 🔥 https://securin.io/zero-day/cve-2026-42374-hardcoded-telnet-backdoor-in-d-link-dir-600l-b1-end-of-life- · Exploit
• https://bdu.fstec.ru/vul/2026-06318 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-42374 · Security Note
• https://twitter.com/VulmonFeeds/status/2051424134559596938 · Twitter Post
• https://t.me/CVEtracker/52640 · Telegram Post
• https://twitter.com/lyrie_ai/status/2054441746159784042 · Twitter Post
• https://t.me/cveNotify/162313 · Telegram Post
• https://twitter.com/lyrie_ai/status/2054441746977661167 · Twitter Post
• https://twitter.com/lyrie_ai/status/2054441744490471545 · Twitter Post
• https://twitter.com/lyrie_ai/status/2054441745279025606 · Twitter Post