CVE-2021-1592

Cisco UCS Manager Software SSH Sessions Denial of Service Vulnerability

MEDIUM
4.3
CVSS Score
Published: August 25, 2021 at 07:11 PM UTC
Updated: June 17, 2026 at 03:32 AM UTC
3 products affected across 1 vendorUnified Computing SystemUnified Computing System 6454Unified Computing System 64108

Using Cisco Unified Computing System (Managed) by Cisco?

Get instant alerts when new vulnerabilities affect Cisco Unified Computing System (Managed) - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
MEDIUM4.3
Exploit prediction
EPSS 1%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

4.0 ≤ v < 4.0(4m)4.1 ≤ v < 4.1(3e)
Affected range stops below 4.0(4m), so it looks safe — our inference, not a vendor statement
Affected range stops below 4.1(3e), so it looks safe — our inference, not a vendor statement
cisco-unified-computing-system-64108 (same device) · cisco-unified-computing-system-6454 (same device)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

4.3MEDIUMcisco
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-664CWE-770

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card