Is CVE-2021-40655 actively exploited?

Yes. KEV Intelligence tracks CVE-2021-40655 as a known exploited vulnerability. Confidence is confirmed.

What exploitation activity has KEV Intelligence observed?

KEV Intelligence has not yet recorded sensor-observed exploitation attempts for CVE-2021-40655. Our sensors continue to monitor for activity targeting this CVE.

Which versions are affected?

CVE-2021-40655 affects D-Link DIR-605 B2 Firmware. Reported affected versions include 2.01mt and b2.

Yes. CVE-2021-40655 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2021-40655

DIR-605 B2 Firmware

D-Link / DIR-605 B2 Firmware · 2.01mt

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Severity: CVSS 7.5 · High
Confidence: Confirmed
Exploit status: Exploited in the wild
EPSS: 86.7%
First observed: —
Last observed: —

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-40655 is an unauthenticated vulnerability affecting D-Link DIR-605 B2 Firmware. An informtion disclosure issue exists in D-LINK-DIR-605 B2 Firmware Version : 2.01MT. An attacker can obtain a user name and...

Is it exploited?

Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.

Who is affected?

D-Link / DIR-605 B2 Firmware 2.01mt.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

An informtion disclosure issue exists in D-LINK-DIR-605 B2 Firmware Version : 2.01MT

An informtion disclosure issue exists in D-LINK-DIR-605 B2 Firmware Version : 2.01MT. An attacker can obtain a user name and password by forging a post request to the / getcfg.php page

Vendor Product Affected Status

dlink dir-605l_firmware 2.01mt Affected

dlink dir-605l b2 Affected

n/a n/a n/a Affected

Published: 24 Sep 2021
Exploitation Reported: 16 May 2024
Attack vector: Remote
Complexity: Low
Privileges: None
User interaction: None

CVE References

CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2021-40655
dlink.com/en/security-bulletin dlink.com · CVE Record https://www.dlink.com/en/security-bulletin/
GitHub — Ilovewomen/D-LINK-DIR-605 github.com · CVE Record https://github.com/Ilovewomen/D-LINK-DIR-605/

Exploitation evidence

Why KEV Intelligence marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 16 May 2024

Independent exploitation attestation added to the KEV Intelligence record.

Proof of concept available

Nuclei Templates

Recorded 12 Jun 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.

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Source	Added
CISA First	2024-05-16 00:00 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets: 0
User-Agents: 0

Raw values available in Pro and Enterprise.

Scanner coverage

Nuclei template detected 01 Jun 2026.

View Nuclei template

Virtual patch status

No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

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Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner	Reference	Detected
Nuclei	https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-40655.yaml	01 Jun 2026
Nessus	https://www.tenable.com/plugins/nessus/197740	02 Jun 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

7.5 High

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

EPSS

86.7%

Weaknesses

Incorrect Authorization CWE-863

All CVSS Scores

CVSS v3.1 7.5 High

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

CVSS v2.0 5.0 Medium

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

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

D-Link DIR-605 - Information Disclosure

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation

12 Jun 2026
Public PoC available

Public proof-of-concept code published
01 Jun 2026
Nuclei template available

Scanner coverage available
02 Jun 2025
Nessus plugin available

Scanner coverage available
16 May 2024
Added to CISA KEV

Listed in the CISA Known Exploited Vulnerabilities catalog
24 Sep 2021
CVE published

Vulnerability disclosed publicly
07 Sep 2021
CVE ID reserved

Identifier reserved by the CNA

Pro API

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Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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Evidence confidence and provenance
First-party sensor telemetry
PoC and scanner references
Affected versions and enrichment
Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2021-40655

Free JSON includes basic KEV fields

{
  "cve_id": "CVE-2021-40655",
  "confidence": "Confirmed",
  "cvss_score": 7.5,
  "cvss_estimated": false,
  "epss_score": 0.86659,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}

Early warning alerts

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