CVE-2017-12336: A vulnerability in the TCL scripting subsystem of Cisco NX-OS System Software could allow an authenticated, local attacker to escape the interactive T...

Description

A vulnerability in the TCL scripting subsystem of Cisco NX-OS System Software could allow an authenticated, local attacker to escape the interactive TCL shell and gain unauthorized access to the underlying operating system of the device. The vulnerability exists due to insufficient input validation of user-supplied files passed to the interactive TCL shell of the affected device. An attacker could exploit this vulnerability to escape the scripting sandbox and execute arbitrary commands on the underlying operating system with the privileges of the authenticated user. To exploit this vulnerability, an attacker must have local access and be authenticated to the targeted device with administrative or tclsh execution privileges. This vulnerability affects the following products running Cisco NX-OS System Software: Multilayer Director Switches, Nexus 2000 Series Fabric Extenders, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 5000 Series Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches in standalone NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, Unified Computing System Manager. Cisco Bug IDs: CSCve93750, CSCve93762, CSCve93763, CSCvg04127.

Metrics

EPSS Probability

0.43%

34.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Cisco	Nx-Os	6.0\(2\)a8\(3\)
Cisco	Nx-Os	8.0\(1\)
Cisco	Nx-Os	8.1\(0\)bd\(0.20\)
Cisco	Nx-Os	8.1\(0.2\)s0
Cisco	Nx-Os	8.1\(0.59\)s0
Cisco	Nx-Os	8.1\(1\)s5
Cisco	Unified Computing System	7.0\(0\)hsk\(0.357\)

References

http://www.securityfocus.com/bid/102168
http://www.securitytracker.com/id/1039936Third Party Advisory, VDB Entry
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20171129-nxos5Vendor Advisory
http://www.securityfocus.com/bid/102168
http://www.securitytracker.com/id/1039936Third Party Advisory, VDB Entry
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20171129-nxos5Vendor Advisory

Timeline

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

Frequently Asked Questions

What is CVE-2017-12336?

A vulnerability in the TCL scripting subsystem of Cisco NX-OS System Software could allow an authenticated, local attacker to escape the interactive TCL shell and gain unauthorized access to the underlying operating system of the device. The vulnerability exists due to insufficient input validation of user-supplied files passed to the interactive TCL shell of the affected device. An attacker could exploit this vulnerability to escape the scripting sandbox and execute arbitrary commands on the underlying operating system with the privileges of the authenticated user. To exploit this vulnerability, an attacker must have local access and be authenticated to the targeted device with administrative or tclsh execution privileges. This vulnerability affects the following products running Cisco NX-OS System Software: Multilayer Director Switches, Nexus 2000 Series Fabric Extenders, Nexus 3000 Series Switches, Nexus 3500 Platform Switches, Nexus 5000 Series Switches, Nexus 5500 Platform Switches, Nexus 5600 Platform Switches, Nexus 6000 Series Switches, Nexus 7000 Series Switches, Nexus 7700 Series Switches, Nexus 9000 Series Switches in standalone NX-OS mode, Nexus 9500 R-Series Line Cards and Fabric Modules, Unified Computing System Manager. Cisco Bug IDs: CSCve93750, CSCve93762, CSCve93763, CSCvg04127.

How severe is CVE-2017-12336?

Severity scoring for CVE-2017-12336 is pending analysis. The EPSS model estimates a 0.43% probability of exploitation in the next 30 days.

How do I fix CVE-2017-12336?

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.