Vulnerability-Lookup

FKIE_CVE-2026-42374

Vulnerability from fkie_nvd - Published: 2026-05-04 17:16 - Updated: 2026-06-17 10:47

Severity

9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.8 (High) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

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.

References

	URL	Tags
	33c584b5-0579-4c06-b2a0-8d8329fcab9c	https://www.securin.io/zero-day/cve-2026-42374-hardcoded-telnet-backdoor-in-d-link-dir-600l-b1-end-of-life-	Exploit, Third Party Advisory
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://www.securin.io/zero-day/cve-2026-42374-hardcoded-telnet-backdoor-in-d-link-dir-600l-b1-end-of-life-	Exploit, Third Party Advisory

Impacted products

	Vendor	Product	Version
	dlink	dir-600l_firmware	*
	dlink	dir-600l	b1

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "cpes": [
            "cpe:2.3:o:dlink:dir-600l_firmware:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "affected",
          "platforms": [
            "MIPS32 Big-Endian"
          ],
          "product": "DIR-600L Firmware",
          "vendor": "D-Link",
          "versions": [
            {
              "status": "affected",
              "version": "B1",
              "versionType": "custom"
            }
          ]
        }
      ],
      "source": "33c584b5-0579-4c06-b2a0-8d8329fcab9c"
    }
  ],
  "configurations": [
    {
      "nodes": [
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          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:dlink:dir-600l_firmware:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "585AD6F9-C845-430D-B77B-7463872EAD98",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        },
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:h:dlink:dir-600l:b1:*:*:*:*:*:*:*",
              "matchCriteriaId": "6966FB89-8C98-4FA3-B4CA-21CAD495A830",
              "vulnerable": false
            }
          ],
          "negate": false,
          "operator": "OR"
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      "operator": "AND"
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  ],
  "cveTags": [
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      "tags": [
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      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "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.\u00a0 The device has reached End-of-Life (EOL) and will not receive patches."
    }
  ],
  "id": "CVE-2026-42374",
  "lastModified": "2026-06-17T10:47:45.933",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
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        "type": "Secondary"
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          "attackVector": "ADJACENT_NETWORK",
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          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
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          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
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        "impactScore": 5.9,
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          "options": [
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            },
            {
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            },
            {
              "technicalImpact": "total"
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          "role": "CISA Coordinator",
          "timestamp": "2026-05-05T03:56:22.870524Z",
          "version": "2.0.3"
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  "published": "2026-05-04T17:16:25.703",
  "references": [
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  "vulnStatus": "Analyzed",
  "weaknesses": [
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        {
          "lang": "en",
          "value": "CWE-798"
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      ],
      "source": "33c584b5-0579-4c06-b2a0-8d8329fcab9c",
      "type": "Secondary"
    }
  ]
}

CVE-2026-42374 (GCVE-0-2026-42374)

Vulnerability from cvelistv5 – Published: 2026-05-04 16:00 – Updated: 2026-05-05 12:43 Unsupported When Assigned

Title

D-Link DIR-600L B1 Hardcoded Telnet Backdoor Credentials

Summary

Severity

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-05-05 03:56 UTC

CWE

CWE-798 - Use of Hard-coded Credentials

Assigner

securin mitre root

References

1 reference

URL	Tags
https://www.securin.io/zero-day/cve-2026-42374-ha…

Impacted products

1 product

Vendor	Product	Version
D-Link	DIR-600L Firmware	Affected: B1 (custom) cpe:2.3:o:dlink:dir-600l_firmware::::::::

Date Public

2026-04-24 00:00

Credits

Arjun Basnet from Securin Labs

Show details on NVD website

JSON

To clipboard

{
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        "metrics": [
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                "id": "CVE-2026-42374",
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                  },
                  {
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                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-05-05T03:56:22.870524Z",
                "version": "2.0.3"
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        "title": "CISA ADP Vulnrichment"
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    ],
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.