CVE-2026-20051

Adjacent denial of service via EVPN traffic loop

Published Feb 25, 2026 · Updated Feb 25, 2026

Denial of service in Cisco NX-OS EVPN ingress processing allows attackers to drop all data-plane traffic through crafted Ethernet frames. The ingress path mishandles crafted Layer 2 frames and creates a persistent VxLAN traffic loop that oversubscribes interface bandwidth. Exploitation requires Layer 2 adjacency, an affected Nexus 3600 or 9500-R PID, and EVPN configuration; the resulting loop interrupts all data-plane traffic.

CVSS severity7.4
High
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Denial of service in Cisco NX-OS EVPN ingress processing allows attackers to drop all data-plane traffic through crafted Ethernet frames. The ingress path mishandles crafted Layer 2 frames and creates a persistent VxLAN traffic loop that oversubscribes interface bandwidth. Exploitation requires Layer 2 adjacency, an affected Nexus 3600 or 9500-R PID, and EVPN configuration; the resulting loop interrupts all data-plane traffic.

The record

CVE
CVE-2026-20051
Published
Feb 25, 2026
Updated
Feb 25, 2026
Vendor
ClamAV
Product
Cisco NX-OS
Classifications
CWE-457, T1498
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.2(1)
  2. Affected versionversion=10.2(1q)
  3. Affected versionversion=10.2(2)
  4. Affected versionversion=10.2(2a)
  5. Affected versionversion=10.2(3)
  6. Affected versionversion=10.2(3t)
  7. Affected versionversion=10.2(3v)
  8. Affected versionversion=10.2(4)
  9. Affected versionversion=10.2(5)
  10. Affected versionversion=10.2(6)
  11. Affected versionversion=10.2(7)
  12. Affected versionversion=10.2(8)
  13. Affected versionversion=10.2(9)
  14. Affected versionversion=10.3(1)
  15. Affected versionversion=10.3(2)
  16. Affected versionversion=10.3(3)
  17. Affected versionversion=10.3(3o)
  18. Affected versionversion=10.3(3p)
  19. Affected versionversion=10.3(3q)
  20. Affected versionversion=10.3(3r)
  21. Affected versionversion=10.3(3w)
  22. Affected versionversion=10.3(3x)
  23. Affected versionversion=10.3(4)
  24. Affected versionversion=10.3(4a)
  25. Affected versionversion=10.3(4g)
  26. Affected versionversion=10.3(4h)
  27. Affected versionversion=10.3(5)
  28. Affected versionversion=10.3(6)
  29. Affected versionversion=10.3(7)
  30. Affected versionversion=10.3(8)
  31. Affected versionversion=10.4(1)
  32. Affected versionversion=10.4(2)
  33. Affected versionversion=10.4(3)
  34. Affected versionversion=10.4(4)
  35. Affected versionversion=10.4(4g)
  36. Affected versionversion=10.4(5)
  37. Affected versionversion=10.4(6)
  38. Affected versionversion=10.5(1)
  39. Affected versionversion=10.5(2)
  40. Affected versionversion=10.5(3)
  41. Affected versionversion=10.5(3e)
  42. Affected versionversion=10.5(3o)
  43. Affected versionversion=10.5(3p)
  44. Affected versionversion=10.5(3s)
  45. Affected versionversion=10.5(3t)
  46. Affected versionversion=10.5(4)
  47. Affected versionversion=10.6(1)
  48. Affected versionversion=10.6(1s)
  49. Affected versionversion=9.2(1)
  50. Affected versionversion=9.2(2)
  51. Affected versionversion=9.2(2t)
  52. Affected versionversion=9.2(2v)
  53. Affected versionversion=9.2(3)
  54. Affected versionversion=9.2(3y)
  55. Affected versionversion=9.2(4)
  56. Affected versionversion=9.3(1)
  57. Affected versionversion=9.3(10)
  58. Affected versionversion=9.3(11)
  59. Affected versionversion=9.3(12)
  60. Affected versionversion=9.3(13)
  61. Affected versionversion=9.3(14)
  62. Affected versionversion=9.3(15)
  63. Affected versionversion=9.3(16)
  64. Affected versionversion=9.3(1z)
  65. Affected versionversion=9.3(2)
  66. Affected versionversion=9.3(3)
  67. Affected versionversion=9.3(4)
  68. Affected versionversion=9.3(5)
  69. Affected versionversion=9.3(5w)
  70. Affected versionversion=9.3(6)
  71. Affected versionversion=9.3(7)
  72. Affected versionversion=9.3(7a)
  73. Affected versionversion=9.3(7k)
  74. Affected versionversion=9.3(8)
  75. Affected versionversion=9.3(9)

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco NX-OSversion=10.2(1); version=10.2(1q); version=10.2(2); version=10.2(2a); version=10.2(3); version=10.2(3t); version=10.2(3v); version=10.2(4); version=10.2(5); version=10.2(6); version=10.2(7); version=10.2(8); version=10.2(9); version=10.3(1); version=10.3(2); version=10.3(3); version=10.3(3o); version=10.3(3p); version=10.3(3q); version=10.3(3r); version=10.3(3w); version=10.3(3x); version=10.3(4); version=10.3(4a); version=10.3(4g); version=10.3(4h); version=10.3(5); version=10.3(6); version=10.3(7); version=10.3(8); version=10.4(1); version=10.4(2); version=10.4(3); version=10.4(4); version=10.4(4g); version=10.4(5); version=10.4(6); version=10.5(1); version=10.5(2); version=10.5(3); version=10.5(3e); version=10.5(3o); version=10.5(3p); version=10.5(3s); version=10.5(3t); version=10.5(4); version=10.6(1); version=10.6(1s); version=9.2(1); version=9.2(2); version=9.2(2t); version=9.2(2v); version=9.2(3); version=9.2(3y); version=9.2(4); version=9.3(1); version=9.3(10); version=9.3(11); version=9.3(12); version=9.3(13); version=9.3(14); version=9.3(15); version=9.3(16); version=9.3(1z); version=9.3(2); version=9.3(3); version=9.3(4); version=9.3(5); version=9.3(5w); version=9.3(6); version=9.3(7); version=9.3(7a); version=9.3(7k); version=9.3(8); version=9.3(9)

Published CVSS scores

7.4Cisco Systems, Inc.CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-457Use of Uninitialized Variable
T1498Network Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo