BugZero | Cisco BugID CSCvn50443 - Cisco NX-OS Software Remote Management Memory Leak...

Cisco - Defect ID: CSCvn50443

Cisco NX-OS Software Remote Management Memory Leak Denial of Service Vulnerability

Cisco - Defect ID: CSCvn50443

Cisco NX-OS Software Remote Management Memory Leak Denial of Service Vulnerability

Last updated on February 21st, 2026

BugZero Risk Score
6.1 Medium

Overall: 6.1

Severity: 6.4

Lifecycle: 9.1

Popularity: 4.6

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Bug Details

Description

Symptom

A vulnerability in the Virtual Shell (VSH) session management for Cisco NX-OS Software could allow an authenticated, remote attacker to cause a VSH process to fail to delete upon termination. This can lead to a build-up of VSH processes that overtime can deplete system memory. When there is no system memory available, this can cause unexpected system behaviors and crashes. The vulnerability is due to the VSH process not being properly deleted when a remote management connection to the device is disconnected. An attacker could exploit this vulnerability by repeatedly performing a remote management connection to the device and terminating the connection in an unexpected manner. A successful exploit could allow the attacker to cause the VSH processes to fail to delete, which can lead to a system-wide denial of service (DoS) condition. The attacker must have valid user credentials to log in into the device via the remote management connection. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190828-nxos-memleak-dos

Conditions

Please refer to the Security Advisory.

Workaround

Please refer to the Security Advisory.

Further Problem Description

Please refer to the Security Advisory.

PSIRT Evaluation

The Cisco PSIRT has assigned this bug the following CVSS version 3 score. The Base CVSS score as of the time of evaluation is 7.7: https://tools.cisco.com/security/center/cvssCalculator.x?version=3.0&vector=CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H CVE ID CVE-2019-1965 has been assigned to document this issue. Additional information on Cisco''s security vulnerability policy can be found at the following URL: http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html

Change history

2025-12-05 Added: 6.2(10), 6.2(12), 6.2(14), 6.2(16), 6.2(18), 6.2(2), 6.2(20), 6.2(20a), 6.2(2a), 6.2(6), 6.2(6a), 6.2(6b), 6.2(8), 6.2(8a), 6.2(8b), 7.2(0)D1(1), 7.2(1)D1(1), 7.2(2)D1(1), 7.2(2)D1(2), 7.3(0)D1(1), 7.3(0)DX(1), 7.3(1)D1(1), 7.3(2)D1(1), 7.3(2)D1(2), 7.3(2)D1(3), 7.3(2)D1(3a), 7.3(3)D1(1), 8.0(1), 8.1(1), 8.1(2), 8.1(2a), 8.2(1), 8.2(2), 8.3(1), 8.3(2)

Relevant Products

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Affected versions:6.2(10), 6.2(12), 6.2(14), 6.2(16), 6.2(18), 6.2(2), 6.2(20), 6.2(20a), 6.2(2a), 6.2(6), 6.2(6a), 6.2(6b), 6.2(8), 6.2(8a), 6.2(8b), 7.2(0)D1(1), 7.2(1)D1(1), 7.2(2)D1(1), 7.2(2)D1(2), 7.3(0)D1(1), 7.3(0)DX(1), 7.3(1)D1(1), 7.3(2)D1(1), 7.3(2)D1(2), 7.3(2)D1(3), 7.3(2)D1(3a), 7.3(3)D1(1), 8.0(1), 8.1(1), 8.1(2), 8.1(2a), 8.2(1), 8.2(2), 8.3(1), 8.3(2)

Fixed versions: 6.2(22), 6.2(24), 6.2(24a), 7.3(4)D1(1), 7.3(5)D1(1), 7.3(6)D1(1), 7.3(7)D1(1), 7.3(8)D1(1), 7.3(9)D1(1), 8.2(10), 8.2(11), 8.2(3), 8.2(4), 8.2(5), 8.2(6), 8.2(7), 8.2(7a), 8.2(8), 8.2(9), 8.4(1), 8.4(10), 8.4(11), 8.4(12), 8.4(13), 8.4(2), 8.4(3), 8.4(4), 8.4(4a), 8.4(5), 8.4(6), 8.4(6a), 8.4(7), 8.4(8), 8.4(9)

Relevant Products

Click on a version to see all relevant bugs

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Cisco - Defect ID: CSCvn50443

Cisco NX-OS Software Remote Management Memory Leak Denial of Service Vulnerability

Cisco - Defect ID: CSCvn50443

Cisco NX-OS Software Remote Management Memory Leak Denial of Service Vulnerability

Last updated on February 21st, 2026

BugZero Risk Score6.1 Medium

Bug Details

Symptom

Conditions

Workaround

Further Problem Description

PSIRT Evaluation

Top Cisco Defects

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BugZero Risk Score
6.1 Medium