CVE-2021-40655

CRITICALNVD 7.59.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2024-05-16), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 7.5 retained for reference. Confidence: HIGH.

Triggered by: CISA KEV (actively exploited)
Sources: cisa_kev, epss, ghsa, nvd
Trending — 4 sources updated this weekExploited in the wild
9.0EG
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS PROB: 87%CVSS: 7.5Exploit: cisa kev · ssvc active · epss top5pct · epss high · public exploitExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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

CVSS v3
7.5
EG Score
9.0(high)
EG Risk
81(Attend)
EG Risk 81/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation100% × 40%
Automatability0% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
87%
EPSS %ILE
100%
KEV
⚠ Exploited

Published

September 24, 2021

Last Modified

November 10, 2025

Advisory Details (3)

Auto-updated Jun 5, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: cisa.
cisa Patch Available🔴 Active Exploitation

Known Exploited Vulnerabilities Catalog | CISA

Known Exploited Vulnerabilities Catalog | CISA. Listed in CISA Known Exploited Vulnerabilities catalog.

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40655
generic

Security Bulletin | D-Link

https://www.dlink.com/en/security-bulletin/
generic

GitHub - Ilovewomen/D-LINK-DIR-605 · GitHub

https://github.com/Ilovewomen/D-LINK-DIR-605/

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 55× in last 7d / 237× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 833 total refreshes for this CVE.

  1. 2026-09-19 22:43 UTCGHSA enrichment
  2. 2026-09-19 18:58 UTCEG score recompute
  3. 2026-09-19 18:58 UTCGHSA enrichment
  4. 2026-09-19 15:38 UTCEPSS rescore
  5. 2026-09-19 15:13 UTCGHSA enrichment
  6. 2026-09-19 11:27 UTCGHSA enrichment
  7. 2026-09-19 07:42 UTCGHSA enrichment
  8. 2026-09-19 03:57 UTCGHSA enrichment
  9. 2026-09-19 00:12 UTCGHSA enrichment
  10. 2026-09-18 20:27 UTCGHSA enrichment
  11. 2026-09-18 19:20 UTCCISA KEV update
  12. 2026-09-18 16:42 UTCGHSA enrichment
  13. 2026-09-18 14:15 UTCCISA KEV update
  14. 2026-09-18 12:57 UTCGHSA enrichment
  15. 2026-09-18 09:12 UTCGHSA enrichment
  16. 2026-09-18 05:27 UTCGHSA enrichment
  17. 2026-09-18 01:42 UTCGHSA enrichment
  18. 2026-09-17 21:57 UTCEG score recompute
  19. 2026-09-17 21:57 UTCGHSA enrichment
  20. 2026-09-17 19:23 UTCEPSS rescore
  21. 2026-09-17 19:23 UTCEPSS rescore
  22. 2026-09-17 18:11 UTCGHSA enrichment
  23. 2026-09-17 14:25 UTCGHSA enrichment
  24. 2026-09-17 10:40 UTCGHSA enrichment
  25. 2026-09-17 06:54 UTCGHSA enrichment
Show 75 more
  1. 2026-09-17 03:09 UTCGHSA enrichment
  2. 2026-09-16 23:24 UTCGHSA enrichment
  3. 2026-09-16 19:39 UTCGHSA enrichment
  4. 2026-09-16 15:54 UTCEG score recompute
  5. 2026-09-16 15:54 UTCGHSA enrichment
  6. 2026-09-16 14:10 UTCCISA KEV update
  7. 2026-09-16 14:05 UTCEPSS rescore
  8. 2026-09-16 12:10 UTCGHSA enrichment
  9. 2026-09-16 08:24 UTCGHSA enrichment
  10. 2026-09-16 04:38 UTCGHSA enrichment
  11. 2026-09-16 00:53 UTCGHSA enrichment
  12. 2026-09-15 21:08 UTCGHSA enrichment
  13. 2026-09-15 17:23 UTCGHSA enrichment
  14. 2026-09-15 13:38 UTCGHSA enrichment
  15. 2026-09-15 09:53 UTCGHSA enrichment
  16. 2026-09-15 06:08 UTCGHSA enrichment
  17. 2026-09-15 02:23 UTCGHSA enrichment
  18. 2026-09-14 22:38 UTCGHSA enrichment
  19. 2026-09-14 19:24 UTCCISA KEV update
  20. 2026-09-14 18:52 UTCGHSA enrichment
  21. 2026-09-14 15:05 UTCGHSA enrichment
  22. 2026-09-14 11:20 UTCGHSA enrichment
  23. 2026-09-14 07:35 UTCGHSA enrichment
  24. 2026-09-14 03:51 UTCGHSA enrichment
  25. 2026-09-14 00:06 UTCGHSA enrichment
  26. 2026-09-13 20:21 UTCGHSA enrichment
  27. 2026-09-13 16:36 UTCGHSA enrichment
  28. 2026-09-13 12:51 UTCGHSA enrichment
  29. 2026-09-13 09:05 UTCGHSA enrichment
  30. 2026-09-13 05:21 UTCGHSA enrichment
  31. 2026-09-13 01:36 UTCGHSA enrichment
  32. 2026-09-12 21:51 UTCGHSA enrichment
  33. 2026-09-12 18:05 UTCEG score recompute
  34. 2026-09-12 18:05 UTCGHSA enrichment
  35. 2026-09-12 14:57 UTCEPSS rescore
  36. 2026-09-12 14:20 UTCGHSA enrichment
  37. 2026-09-12 10:34 UTCGHSA enrichment
  38. 2026-09-12 06:48 UTCGHSA enrichment
  39. 2026-09-12 03:04 UTCGHSA enrichment
  40. 2026-09-11 23:19 UTCGHSA enrichment
  41. 2026-09-11 19:34 UTCGHSA enrichment
  42. 2026-09-11 18:49 UTCCISA KEV update
  43. 2026-09-11 15:49 UTCGHSA enrichment
  44. 2026-09-11 12:04 UTCGHSA enrichment
  45. 2026-09-11 08:19 UTCGHSA enrichment
  46. 2026-09-11 04:34 UTCGHSA enrichment
  47. 2026-09-11 00:49 UTCGHSA enrichment
  48. 2026-09-10 21:04 UTCGHSA enrichment
  49. 2026-09-10 19:28 UTCCISA KEV update
  50. 2026-09-10 17:18 UTCGHSA enrichment
  51. 2026-09-10 13:33 UTCGHSA enrichment
  52. 2026-09-10 09:48 UTCGHSA enrichment
  53. 2026-09-10 06:03 UTCGHSA enrichment
  54. 2026-09-10 02:16 UTCGHSA enrichment
  55. 2026-09-09 22:32 UTCGHSA enrichment
  56. 2026-09-09 19:08 UTCCISA KEV update
  57. 2026-09-09 18:47 UTCGHSA enrichment
  58. 2026-09-09 15:02 UTCGHSA enrichment
  59. 2026-09-09 11:17 UTCGHSA enrichment
  60. 2026-09-09 07:32 UTCGHSA enrichment
  61. 2026-09-09 03:47 UTCGHSA enrichment
  62. 2026-09-09 00:02 UTCGHSA enrichment
  63. 2026-09-08 20:17 UTCGHSA enrichment
  64. 2026-09-08 18:54 UTCCISA KEV update
  65. 2026-09-08 16:31 UTCGHSA enrichment
  66. 2026-09-08 12:42 UTCGHSA enrichment
  67. 2026-09-08 08:55 UTCGHSA enrichment
  68. 2026-09-08 05:08 UTCGHSA enrichment
  69. 2026-09-08 01:20 UTCGHSA enrichment
  70. 2026-09-07 21:36 UTCGHSA enrichment
  71. 2026-09-07 17:51 UTCGHSA enrichment
  72. 2026-09-07 14:05 UTCGHSA enrichment
  73. 2026-09-07 10:19 UTCGHSA enrichment
  74. 2026-09-07 06:34 UTCGHSA enrichment
  75. 2026-09-07 02:48 UTCGHSA enrichment

Publicly available exploits

(1 reference)

Working exploit code is in the public domain. Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Nucleihttp/cves/2021/CVE-2021-40655.yaml
    First seen Jan 1, 2021

    D-Link DIR-605 - Information Disclosure

    Open source ↗

Frequently asked(6)

What is CVE-2021-40655?
CVE-2021-40655 is a critical vulnerability published on September 24, 2021. 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
When was CVE-2021-40655 disclosed?
CVE-2021-40655 was first published in the National Vulnerability Database on September 24, 2021, with the most recent update on November 10, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-40655 actively exploited?
Yes. CISA added CVE-2021-40655 to the Known Exploited Vulnerabilities catalog on May 16, 2024, affecting D-Link DIR-605 Router. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2021-40655?
CVE-2021-40655 has a CVSS v3 base score of 7.5 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2021-40655?
CVE-2021-40655 affects D-Link DIR-605 Router. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.
How do I remediate CVE-2021-40655?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-40655, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2021-40655

Explore →

Is Your Infrastructure Affected by CVE-2021-40655?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs