PT-2026-36836 · D Link · Dir600L

Arjun Basnet · Published 2026-04-20 · Updated 2026-05-13 · CVE-2026-42375

Positive Technologies (AI Summary)

CVSS v2.0

10

Critical

Base vector

AV:N/AC:L/Au:N/C:C/I:C/A:C

Name of the Vulnerable Software and Affected Versions D-Link DIR-600L Hardware Revision A1

Description A hardcoded telnet backdoor exists in the device. At boot, the device starts a telnet daemon via the /bin/telnetd.sh script using the username "Alphanetworks" and a static password "wrgn35 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 exploit this 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:2026-06317

CVE-2026-42375

Affected Products

Dir600L

References · 11

• 🔥 https://securin.io/zero-day/cve-2026-42375-hardcoded-telnet-backdoor-in-d-link-dir-600l-a1-end-of-life- · Exploit
• https://nvd.nist.gov/vuln/detail/CVE-2026-42375 · Security Note
• https://bdu.fstec.ru/vul/2026-06317 · Security Note
• https://t.me/cveNotify/162314 · Telegram Post
• https://t.me/CVEtracker/52641 · Telegram Post
• https://twitter.com/lyrie_ai/status/2054448299734700199 · Twitter Post
• https://twitter.com/lyrie_ai/status/2054448302792266190 · Twitter Post
• https://twitter.com/vuldb/status/2051343242172748263 · Twitter Post
• https://twitter.com/VulmonFeeds/status/2051421575065338236 · Twitter Post
• https://twitter.com/lyrie_ai/status/2054448300670009584 · Twitter Post
• https://twitter.com/lyrie_ai/status/2054448301697650797 · Twitter Post