Hardcoded Telnet Backdoor in D-Link DIR-600L A1 Router
CVE-2026-42375

9.8CRITICAL

Key Information:

Vendor

D-link
Status
Dir-600l Firmware
Vendor
CVE Published:
4 May 2026

What is CVE-2026-42375?

The D-Link DIR-600L A1 router presents a significant security risk due to a hardcoded telnet backdoor implemented through a default username and static password. This vulnerability allows unauthorized local network attackers to gain root access, compromising the entire device. Given its End-of-Life status, it will not receive any patches, making it imperative for users to take immediate action to secure their networks against potential exploits.

Affected Version(s)

DIR-600L Firmware MIPS32 Big-Endian A1

References

https://www.securin.io/zero-day/cve-2026-42375-hardcoded-...

CVSS V3.1

Score:
9.8
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Arjun Basnet from Securin Labs
.