CVE-2019-1965: A vulnerability in the Virtual Shell (VSH) session management for Cisco NX-OS Software could allow an authenticated, remote attacker to cause a VSH pr...

Description

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 to the device using the remote management connection.

Metrics

CVSS 3.1

7.7/10

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

EPSS Probability

1.52%

71.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Cisco	Nx-Os	>= 5.2, < 6.2\(29\)
Cisco	Nx-Os	>= 7.3, < 8.4
Cisco	Nx-Os	>= 7.0\(3\)f, < 9.2
Cisco	Nx-Os	< 7.1\(5\)n1\(1b\)
Cisco	Nx-Os	>= 7.3, < 7.3\(5\)n1\(1\)
Cisco	Nx-Os	< 6.2\(22\)
Cisco	Nx-Os	>= 7.2, < 7.3\(4\)d1\(1\)
Cisco	Nx-Os	>= 8.0, < 8.2\(3\)
Cisco	Nx-Os	>= 8.3, < 8.4
Cisco	Nx-Os	< 7.0\(3\)i4\(9\)
Cisco	Nx-Os	>= 7.0\(3\)i7, < 7.0\(3\)i7\(4\)
Cisco	Nx-Os	>= 7.0\(3\)i7, < 7.0\(3\)i7\(6\)
Cisco	Nx-Os	>= 9.2, < 9.2\(3\)
Cisco	Nx-Os	< 3.2\(3k\)
Cisco	Nx-Os	>= 4.0, < 4.0\(2e\)

References

Timeline

Published: Aug 28, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-1965?

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 to the device using the remote management connection.

How severe is CVE-2019-1965?

CVE-2019-1965 has a CVSS score of 7.7/10 (HIGH severity). The EPSS model estimates a 1.52% probability of exploitation in the next 30 days.

How do I fix CVE-2019-1965?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.