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CVE-2021-1387 Cisco NX-OS

Affected softwareCisco NX-OS
Severity8.6 High CVSS 3.1 3 scores
WeaknessCWE-401
Published24 Feb 2021
Updated17 Jun 2026

Description

A vulnerability in the network stack of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability exists because the software improperly releases resources when it processes certain IPv6 packets that are destined to an affected device. An attacker could exploit this vulnerability by sending multiple crafted IPv6 packets to an affected device. A successful exploit could cause the network stack to run out of available buffers, impairing operations of control plane and management plane protocols and resulting in a DoS condition. Manual intervention would be required to restore normal operations on the affected device. For more information about the impact of this vulnerability, see the Details section of this advisory.

Exploitation status

No public exploit

No exploit has been reported in the sources we check. Published 5 years ago.

  • CISA KEV not listed
  • VulnCheck KEV not listed
  • CISA Vulnrichment no assessment published
  • Indexed PoC none indexed
  • EPSS 1.4% chance in 30 days

Waratek protection

Outside Waratek scope

A Java vulnerability, but not one Waratek protects. It affects only Java on a user's desktop (applets, Web Start, JavaFX, the installer), sits in a product the Waratek agent can't be installed into, or is in a package we don't expect in business applications. The decision below says which.

  • Protection none
  • Action not pursued none
  • Review human Researcher
  • Record active
Decided by Manual classification of this CVE in the legacy dataset
Finding A manual classification set this CVE's status to Outside Waratek scope, but the CVE names a tracked product.

CVSS

8.6 HIGH v3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H 3 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

VersionScoreBandVectorAssignerType
CVSS 3.1 8.6 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H psirt@cisco.com Secondary published
CVSS 3.1 8.6 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H NVD Primary
CVSS 2.0 4.3 none AV:N/AC:M/Au:N/C:N/I:N/A:P NVD Primary

Affected software and releases

Products and versions

2 products, 241 version entries
SourceVendorProductSchemeAffected versions
nvd cisco nx-os generic 6.0\(2\)u2\(1\) · 6.0\(2\)u2\(2\) · 6.0\(2\)u2\(3\) · 6.0\(2\)u2\(4\) · 6.0\(2\)u2\(5\) · 6.0\(2\)u2\(6\) · 6.0\(2\)a3\(1\) · 6.0\(2\)u3\(1\) · 6.0\(2\)a3\(2\) · 6.0\(2\)u3\(2\) · 6.0\(2\)u3\(3\) · 6.0\(2\)a3\(4\) · 6.0\(2\)u3\(4\) · 6.0\(2\)u3\(5\) · 6.0\(2\)u3\(6\) · 6.0\(2\)u3\(7\) · 6.0\(2\)u3\(8\) · 6.0\(2\)u3\(9\) · 6.0\(2\)a4\(1\) · 6.0\(2\)u4\(1\) · 6.0\(2\)a4\(2\) · 6.0\(2\)u4\(2\) · 6.0\(2\)a4\(3\) · 6.0\(2\)u4\(3\) · 6.0\(2\)a4\(4\) · 6.0\(2\)u4\(4\) · 6.0\(2\)a4\(5\) · 6.0\(2\)a4\(6\) · 6.0\(2\)u5\(1\) · 6.0\(2\)u5\(2\) · 6.0\(2\)u5\(3\) · 6.0\(2\)u5\(4\) · 6.0\(2\)a6\(1\) · 6.0\(2\)a6\(1a\) · 6.0\(2\)u6\(1\) · 6.0\(2\)u6\(1a\) · 6.0\(2\)a6\(2\) · 6.0\(2\)a6\(2a\) · 6.0\(2\)u6\(2\) · 6.0\(2\)u6\(2a\) · 6.0\(2\)a6\(3\) · 6.0\(2\)a6\(3a\) · 6.0\(2\)u6\(3\) · 6.0\(2\)u6\(3a\) · 6.0\(2\)a6\(4\) · 6.0\(2\)a6\(4a\) · 6.0\(2\)u6\(4\) · 6.0\(2\)u6\(4a\) · 6.0\(2\)a6\(5\) · 6.0\(2\)a6\(5a\) · 6.0\(2\)a6\(5b\) · 6.0\(2\)u6\(5\) · 6.0\(2\)u6\(5a\) · 6.0\(2\)u6\(5b\) · 6.0\(2\)u6\(5c\) · 6.0\(2\)a6\(6\) · 6.0\(2\)u6\(6\) · 6.0\(2\)a6\(7\) · 6.0\(2\)u6\(7\) · 6.0\(2\)a6\(8\) · 6.0\(2\)u6\(8\) · 6.0\(2\)u6\(9\) · 6.0\(2\)u6\(10\) · 6.0\(2\)u6\(10a\) · 6.0\(2\)a7\(1\) · 6.0\(2\)a7\(1a\) · 6.0\(2\)a7\(2\) · 6.0\(2\)a7\(2a\) · 6.0\(2\)a8\(1\) · 6.0\(2\)a8\(2\) · 6.0\(2\)a8\(3\) · 6.0\(2\)a8\(4\) · 6.0\(2\)a8\(4a\) · 6.0\(2\)a8\(5\) · 6.0\(2\)a8\(6\) · 6.0\(2\)a8\(7\) · 6.0\(2\)a8\(7a\) · 6.0\(2\)a8\(7b\) · 6.0\(2\)a8\(8\) · 6.0\(2\)a8\(9\) · 6.0\(2\)a8\(10\) · 6.0\(2\)a8\(10a\) · 6.0\(2\)a8\(11\) · 6.0\(2\)a8\(11a\) · 6.0\(2\)a8\(11b\) · 7.0\(0\)n1\(1\) · 7.0\(1\)n1\(1\) · 7.0\(2\)n1\(1\) · 7.0\(3\)n1\(1\) · 7.0\(3\)f1\(1\) · 7.0\(3\)i2\(1\) · 7.0\(3\)i2\(1a\) · 7.0\(3\)f2\(1\) · 7.0\(3\)i2\(2\) · 7.0\(3\)i2\(2a\) · 7.0\(3\)i2\(2b\) · 7.0\(3\)i2\(2c\) · 7.0\(3\)i2\(2d\) · 7.0\(3\)i2\(2e\) · 7.0\(3\)i2\(2r\) · 7.0\(3\)i2\(2s\) · 7.0\(3\)i2\(2v\) · 7.0\(3\)i2\(2w\) · 7.0\(3\)i2\(2x\) · 7.0\(3\)i2\(2y\) · 7.0\(3\)f2\(2\) · 7.0\(3\)i2\(3\) · 7.0\(3\)i2\(4\) · 7.0\(3\)i2\(5\) · 7.0\(3\)f3\(1\) · 7.0\(3\)i3\(1\) · 7.0\(3\)im3\(1\) · 7.0\(3\)f3\(2\) · 7.0\(3\)im3\(2\) · 7.0\(3\)im3\(2a\) · 7.0\(3\)im3\(2b\) · 7.0\(3\)f3\(3\) · 7.0\(3\)f3\(3a\) · 7.0\(3\)f3\(3c\) · 7.0\(3\)im3\(3\) · 7.0\(3\)f3\(4\) · 7.0\(3\)f3\(5\) · 7.0\(3\)i4\(1\) · 7.0\(3\)i4\(1t\) · 7.0\(3\)i4\(2\) · 7.0\(3\)i4\(3\) · 7.0\(3\)i4\(4\) · 7.0\(3\)ic4\(4\) · 7.0\(3\)i4\(5\) · 7.0\(3\)i4\(6\) · 7.0\(3\)i4\(6t\) · 7.0\(3\)i4\(7\) · 7.0\(3\)i4\(8\) · 7.0\(3\)i4\(8a\) · 7.0\(3\)i4\(8b\) · 7.0\(3\)i4\(8z\) · 7.0\(3\)i4\(9\) · 7.0\(3\)i5\(1\) · 7.0\(3\)i5\(2\) · 7.0\(3\)i5\(3\) · 7.0\(3\)i5\(3a\) · 7.0\(3\)i5\(3b\) · 7.0\(3\)i6\(1\) · 7.0\(3\)i6\(2\) · 7.0\(3\)i7\(1\) · 7.0\(3\)ia7\(1\) · 7.0\(3\)i7\(2\) · 7.0\(3\)im7\(2\) · 7.0\(3\)ia7\(2\) · 7.0\(3\)i7\(3\) · 7.0\(3\)i7\(3z\) · 7.0\(3\)i7\(4\) · 7.0\(3\)i7\(5\) · 7.0\(3\)i7\(5a\) · 7.0\(3\)i7\(6\) · 7.0\(3\)i7\(6z\) · 7.0\(3\)i7\(7\) · 7.0\(3\)i7\(8\) · 7.0\(4\)n1\(1\) · 7.0\(4\)n1\(1a\) · 7.0\(5\)n1\(1\) · 7.0\(5\)n1\(1a\) · 7.0\(6\)n1\(1\) · 7.0\(6\)n1\(2s\) · 7.0\(6\)n1\(3s\) · 7.0\(6\)n1\(4s\) · 7.0\(7\)n1\(1\) · 7.0\(7\)n1\(1a\) · 7.0\(7\)n1\(1b\) · 7.0\(8\)n1\(1\) · 7.0\(8\)n1\(1a\) · 7.1\(0\)n1\(1\) · 7.1\(0\)n1\(1a\) · 7.1\(0\)n1\(1b\) · 7.1\(1\)n1\(1\) · 7.1\(1\)n1\(1a\) · 7.1\(2\)n1\(1\) · 7.1\(2\)n1\(1a\) · 7.1\(3\)n1\(1\) · 7.1\(3\)n1\(2\) · 7.1\(3\)n1\(2a\) · 7.1\(3\)n1\(3\) · 7.1\(3\)n1\(4\) · 7.1\(3\)n1\(5\) · 7.1\(4\)n1\(1\) · 7.1\(4\)n1\(1a\) · 7.1\(4\)n1\(1c\) · 7.1\(4\)n1\(1d\) · 7.1\(5\)n1\(1\) · 7.1\(5\)n1\(1b\) · 7.2\(0\)n1\(1\) · 7.2\(0\)d1\(1\) · 7.2\(1\)n1\(1\) · 7.2\(1\)d1\(1\) · 7.2\(2\)d1\(1\) · 7.2\(2\)d1\(2\) · 7.2\(2\)d1\(3\) · 7.2\(2\)d1\(4\) · 7.3\(0\)dx\(1\) · 7.3\(0\)n1\(1\) · 7.3\(0\)n1\(1a\) · 7.3\(0\)n1\(1b\) · 7.3\(0\)d1\(1\) · 7.3\(1\)n1\(1\) · 7.3\(1\)d1\(1\) · 7.3\(2\)n1\(1\) · 7.3\(2\)n1\(1b\) · 7.3\(2\)n1\(1c\) · 7.3\(2\)d1\(1\) · 7.3\(2\)d1\(1d\) · 7.3\(2\)d1\(2\) · 7.3\(2\)d1\(3\) · 7.3\(2\)d1\(3a\) · 7.3\(3\)n1\(1\) · 7.3\(3\)d1\(1\) · 7.3\(4\)n1\(1\) · 7.3\(4\)n1\(1a\) · 7.3\(4\)d1\(1\) · 7.3\(5\)n1\(1\) · 7.3\(5\)d1\(1\) · 7.3\(6\)n1\(1\) · 7.3\(6\)n1\(1a\) · 7.3\(6\)d1\(1\) · 7.3\(7\)n1\(1\) · 7.3\(7\)n1\(1a\) · 7.3\(7\)n1\(1b\) · 8.0\(1\) · 8.1\(1\) · 8.1\(2\) · 8.1\(2a\) · 8.2\(1\) · 8.2\(2\) · 8.2\(3\) · 8.2\(4\) · 8.2\(5\) · 8.3\(1\) · 8.3\(2\) · 8.4\(1\) · 8.4\(2\)
nvd cisco unified computing system generic ≥ 4.0 and < 4.0.4 · ≥ 4.1 and < 4.1.1

References

URLTags
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-ipv6-netstack-edXPGV7K Vendor Advisory

Timeline

Published2021-02-24By the CVE Program.
NVD record modified2026-06-17NVD's own last-modified date for this record.