CVE-2020-3566

HIGHNVD 8.69.0▲
EchelonGraph scoreHIGH confidence

Score elevated to 9.0 because this CVE is listed on the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating real-world exploitation has been confirmed by US federal agencies. NVD baseline CVSS 8.6 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
8.6
EchelonGraph verdictPatch nowTreat as an emergency — this is being exploited.
  • Actively exploited in the wild (CISA-KEV)
CISA-KEV: ExploitedEPSS: 4%CVSS: 8.6Exploit: NoneExposed: 0

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

A vulnerability in the Distance Vector Multicast Routing Protocol (DVMRP) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to exhaust process memory of an affected device. The vulnerability is due to insufficient queue management for Internet Group Management Protocol (IGMP) packets. An attacker could exploit this vulnerability by sending crafted IGMP traffic to an affected device. A successful exploit could allow the attacker to cause memory exhaustion, resulting in instability of other processes. These processes may include, but are not limited to, interior and exterior routing protocols. Cisco will release software updates that address this vulnerability.

CVSS v3
8.6
EG Score
9.0(high)
EG Risk
96(Attend)
EG Risk 96/100SSVC: 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%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS
88.3%
KEV
⚠ Exploited

Published

August 29, 2020

Last Modified

October 28, 2025

Advisory Details (2)

Auto-updated Jun 2, 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-2020-3566
generic🔴 Active Exploitation

Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerabilities

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-dvmrp-memexh-dSmpdvfz

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 62× in last 7d / 241× 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 442 total refreshes for this CVE.

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

Related CVEs(same CWE)

Frequently asked(6)

What is CVE-2020-3566?
CVE-2020-3566 is a high vulnerability published on August 29, 2020. A vulnerability in the Distance Vector Multicast Routing Protocol (DVMRP) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to exhaust process memory of an affected device. The vulnerability is due to insufficient queue management for Internet Group Management…
When was CVE-2020-3566 disclosed?
CVE-2020-3566 was first published in the National Vulnerability Database on August 29, 2020, with the most recent update on October 28, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-3566 actively exploited?
Yes. CISA added CVE-2020-3566 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Cisco IOS XR. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.
What is the CVSS score of CVE-2020-3566?
CVE-2020-3566 has a CVSS v3 base score of 8.6 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
Which products are affected by CVE-2020-3566?
CVE-2020-3566 affects Cisco IOS XR. 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-2020-3566?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-3566, 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-2020-3566

Explore →

Is Your Infrastructure Affected by CVE-2020-3566?

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

Start Free Scan →Browse All CVEs