CVE-2017-12340: A vulnerability in Cisco NX-OS System Software running on Cisco MDS Multilayer Director Switches, Cisco Nexus 7000 Series Switches, and Cisco Nexus 77...

Description

A vulnerability in Cisco NX-OS System Software running on Cisco MDS Multilayer Director Switches, Cisco Nexus 7000 Series Switches, and Cisco Nexus 7700 Series Switches could allow an authenticated, local attacker to access the Bash shell of an affected device's operating system, even if the Bash shell is disabled on the system. The vulnerability is due to insufficient sanitization of user-supplied parameters that are passed to certain functions of the Python scripting sandbox of the affected system. An attacker could exploit this vulnerability to escape the scripting sandbox and enter the Bash shell of the operating system with the privileges of the authenticated user for the affected system. To exploit this vulnerability, the attacker must have local access to the affected system and be authenticated to the affected system with administrative or Python execution privileges. Cisco Bug IDs: CSCvd86513.

Metrics

EPSS Probability

0.34%

25.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Cisco	Nx-Os	8.1\(0.70\)s0

References

Timeline

Published: Nov 30, 2017
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2017-12340?

A vulnerability in Cisco NX-OS System Software running on Cisco MDS Multilayer Director Switches, Cisco Nexus 7000 Series Switches, and Cisco Nexus 7700 Series Switches could allow an authenticated, local attacker to access the Bash shell of an affected device's operating system, even if the Bash shell is disabled on the system. The vulnerability is due to insufficient sanitization of user-supplied parameters that are passed to certain functions of the Python scripting sandbox of the affected system. An attacker could exploit this vulnerability to escape the scripting sandbox and enter the Bash shell of the operating system with the privileges of the authenticated user for the affected system. To exploit this vulnerability, the attacker must have local access to the affected system and be authenticated to the affected system with administrative or Python execution privileges. Cisco Bug IDs: CSCvd86513.

How severe is CVE-2017-12340?

Severity scoring for CVE-2017-12340 is pending analysis. The EPSS model estimates a 0.34% probability of exploitation in the next 30 days.

How do I fix CVE-2017-12340?

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.