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Vulnerability record · CVE-2021-1592 · published 25 August 2021

CVE-2021-1592: Cisco unified computing system allocation without limits vulnerability

Cisco · Unified Computing System

A vulnerability in the way Cisco UCS Manager software handles SSH sessions could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper resource management for established SSH sessions. An attacker could exploit this vulnerability by opening a significant number of SSH sessions on an affected device. A successful exploit could allow the attacker to cause a crash and restart of internal Cisco UCS Manager software processes and a temporary loss of access to the Cisco UCS Manager CLI and web UI. Note: The attacker must have valid user credentials to authenticate to the affected device.

4.3 CVSS 3.1 Medium EPSS 1.0% · top 37.6% CWE-664 · CWE-664CWE-770 · Allocation without limits
4.3CVSS 3.1 base score, v2 4.0
1.0%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

A vulnerability in the way Cisco UCS Manager software handles SSH sessions could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper resource management for established SSH sessions. An attacker could exploit this vulnerability by opening a significant number of SSH sessions on an affected device. A successful exploit could allow the attacker to cause a crash and restart of internal Cisco UCS Manager software processes and a temporary loss of access to the Cisco UCS Manager CLI and web UI. Note: The attacker must have valid user credentials to authenticate to the affected device.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucs-ssh-dos-MgvmyrQy PatchVendor Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucs-ssh-dos-MgvmyrQy PatchVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2021-1592), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.