CVE-2023-20040: A vulnerability in the NETCONF service of Cisco Network Services Orchestrator (NSO) could allow an authenticated, remote attacker to cause a denial of...

Description

A vulnerability in the NETCONF service of Cisco Network Services Orchestrator (NSO) could allow an authenticated, remote attacker to cause a denial of service (DoS) on an affected system that is running as the root user. To exploit this vulnerability, the attacker must be a member of the admin group. This vulnerability exists because user-supplied input is not properly validated when NETCONF is used to upload packages to an affected device. An attacker could exploit this vulnerability by uploading a specially crafted package file. A successful exploit could allow the attacker to write crafted files to arbitrary locations on the filesystem or delete arbitrary files from the filesystem of an affected device, resulting in a DoS condition. Note: By default, during install, Cisco NSO will be set up to run as the root user unless the --run-as-user option is used.

Metrics

CVSS 3.1

5.5/10

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

EPSS Probability

1.24%

65.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Cisco	Network Services Orchestrator	>= 3.3, < 5.4.7
Cisco	Network Services Orchestrator	>= 5.5, < 5.5.6
Cisco	Network Services Orchestrator	>= 5.6, < 5.6.7
Cisco	Network Services Orchestrator	>= 5.7, < 5.7.4
Cisco	Network Services Orchestrator	5.8

References

Timeline

Published: Jan 20, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-20040?

A vulnerability in the NETCONF service of Cisco Network Services Orchestrator (NSO) could allow an authenticated, remote attacker to cause a denial of service (DoS) on an affected system that is running as the root user. To exploit this vulnerability, the attacker must be a member of the admin group. This vulnerability exists because user-supplied input is not properly validated when NETCONF is used to upload packages to an affected device. An attacker could exploit this vulnerability by uploading a specially crafted package file. A successful exploit could allow the attacker to write crafted files to arbitrary locations on the filesystem or delete arbitrary files from the filesystem of an affected device, resulting in a DoS condition. Note: By default, during install, Cisco NSO will be set up to run as the root user unless the --run-as-user option is used.

How severe is CVE-2023-20040?

CVE-2023-20040 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 1.24% probability of exploitation in the next 30 days.

How do I fix CVE-2023-20040?

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.