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VulnerabilityPublished

CVE-2026-42374: D-Link DIR-600L Firmware · Use of Hard-coded Credentials

Affects D-Link DIR-600L FirmwareSource CVE Database V5

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Not known to be exploited · CVSS 9.8 Critical · end of life, no fix coming : replace or isolate D-Link DIR-600L Firmware; no fix will be released.

Data as of 1 Nov 2026, 22:58 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.

Contested

Critical score, yet low EPSS after six months
EPSS
0.4% chance of exploitation in 30 days – higher than 40% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
None coming – the product is end of life
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 4 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 1 Nov 2026.

What to do

No fix will be released: D-Link DIR-600L Firmware is end of life. Replace it, or isolate it from untrusted networks until you can.

Affected software

ProductAffectedFixed in
D-LinkDIR-600L FirmwareAffected
  • =B1
Fixed in–

AI-suggested

The device is End-of-Life and will not receive patches or official fixes. Mitigation requires discontinuing use of the affected hardware or isolating it from untrusted local networks to prevent unauthorized access. Network segmentation or disabling telnet access (if possible) may reduce exposure, but no vendor-supported remediation exists.

Description

The D-Link DIR-600L Hardware Revision B1 firmware contains a hardcoded telnet backdoor with fixed credentials. This backdoor starts a telnet daemon at boot using the username "Alphanetworks" and a static password stored in a configuration file. Authentication is performed via a custom login binary using simple string comparison, granting root shell access to any attacker on the local network without prior authentication. The device is End-of-Life and will not receive patches for this vulnerability. The CVSS score is 9.8, indicating critical severity.

References

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