CVE-2021-1592

mediumpriority · track · 17EPSS 0.010 · 64 %ileEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.03% (64th) EPSS

CVSS 4 · medium

Is it mine?

6 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · cisco_csaf

EPSS · scored 2026-10-27

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.

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

FixedCisco Unified Computing System (Managed)cisco_csaf
Cisco has released software updates that address this vulnerability.
https://software.cisco.com

cvss

Technical severity, 0–10. One row per scoring source.

4.3

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.04mediumAV:N/AC:L/Au:S/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 8 · impact 2.9

v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Lprimary · NVD / NIST USexploitability 2.8 · impact 1.4

v3.14.3mediumAV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Lsecondary · FSTEC (BDU) RU

v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Lsecondary · ENISA EU

v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Lsecondary · psirt@cisco.com USexploitability 2.8 · impact 1.4

v3.14mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:Usecondary · CVSS-BT (t0sche)

v3.14.3mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:Lsecondary · Cisco PSIRT US

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-770USprimaryCWE-664USCWE-664US

affected products (6)

Products and version ranges known to be affected.

Cisco Cisco Unified Computing System (Managed)all versionscisco_csafUS
Cisco Cisco Unified Computing System (Managed)≤ n/aenisa_euvdEU
Cisco Systems Inc. Cisco UCS 64004.0 → 4.0(4m)fstec_bduRU
Cisco Systems Inc. Cisco UCS 64004.1 → 4.1(3e)fstec_bduRU
cisco unified computing system4.0 → 4.0\(4m\)nvdUScpe:2.3:a:cisco:unified_computing_system:*:*:*:*:*:*:*:*
cisco unified computing system4.1 → 4.1\(3e\)nvdUScpe:2.3:a:cisco:unified_computing_system:*:*:*:*:*:*:*:*

advisories (1)

Vendor and ecosystem advisories describing this.

cisco-sa-ucs-ssh-dos-MgvmyrQyCisco UCS Manager Software SSH Sessions Denial of Service Vulnerability2021-08-25csaf · cisco_csafUS
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. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is part of the August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: August 2021 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74640"].

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu cisco_csaf nvd NVD CVE.org MITRE

published 2021-08-25modified 2026-06-17

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+3264 more

references (6)

External citations — patches, advisories, analysis.

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