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CVE-2021-1590 Cisco NX-OS

Affected softwareCisco NX-OS
Severity5.3 Medium CVSS 3.1 3 scores
WeaknessOut-of-bounds write (CWE-787)
Published25 Aug 2021
Updated17 Jun 2026

Description

A vulnerability in the implementation of the system login block-for command for Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a login process to unexpectedly restart, causing a denial of service (DoS) condition. This vulnerability is due to a logic error in the implementation of the system login block-for command when an attack is detected and acted upon. An attacker could exploit this vulnerability by performing a brute-force login attack on an affected device. A successful exploit could allow the attacker to cause a login process to reload, which could result in a delay during authentication to the affected device.

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 automated Upstream data
  • Record active
Decided by The only affected product being a sealed appliance image, where Java runs but no -javaagent can be attached
Finding This CVE names only products the Waratek agent cannot be installed into (cisco/unified_computing_system). They ship as sealed appliance images or as native code with no application JVM, so there is no start-up line to add -javaagent to. The vulnerability may well be a Java one; it is permanently out of ARMR's reach rather than outside its subject.

CVSS

5.3 MEDIUM v3.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L 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 5.3 MEDIUM CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L psirt@cisco.com Secondary published
CVSS 3.1 5.3 MEDIUM CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L 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, 4 version entries
SourceVendorProductSchemeAffected versions
nvd cisco nx-os generic 7.0\(3\)i4\(0.116\) · 7.3\(7\)n1\(1b\)
nvd cisco unified computing system generic < 4.0.4 · ≥ 4.1 and < 4.1.3

References

URLTags
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-nxos-login-blockfor-RwjGVEcu Patch, Vendor Advisory

Timeline

Published2021-08-25By the CVE Program.
NVD record modified2026-06-17NVD's own last-modified date for this record.