CVE-2017-12339 [Medium] | Code Injection in Nx-Os

A vulnerability in the CLI of Cisco NX-OS System Software could allow an authenticated, local attacker to perform a command injection attack. The vulnerability is due to insufficient input validation of command arguments to the CLI parser. An attacker could exploit this vulnerability by injecting crafted command arguments into a vulnerable CLI command. An exploit could allow the attacker to execute arbitrary commands at the user's privilege level. On products that support multiple virtual device contexts (VDCs), this vulnerability could allow the attacker to execute commands at the user's privilege level outside the user's environment. 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 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 Fabric Switches in Application Centric Infrastructure (ACI) mode, Nexus 9000 Series Switches in standalone NX-OS mode, and Nexus 9500 R-Series Line Cards and Fabric Modules. Cisco Bug IDs: CSCve99925, CSCvf15164, CSCvf15167, CSCvf15170, CSCvf15173.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.19%	0.70%	+0.51%
2	2026-01-12	0.08%	0.19%	+0.10%
3	2025-03-17	—	0.08%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.19%

0.70%

+0.51%

2026-01-12

0.08%

0.19%

+0.10%

2025-03-17

—

0.08%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
5.7	3.0	MEDIUM	`CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L` Click to expand Attack vector (AV:L) They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:H) They need powerful rights—admin, root, or similar—before this pays off. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:C) Breaking this can reach past the original component and bite other resources—bigger blast radius. Confidentiality (C:L) Some sensitive info could get out, but not a total data dump. Integrity (I:L) Attackers could change some data, but it’s limited—not everything goes. Availability (A:L) Might cause slowdowns, glitches, or partial disruption—not a full brick.	1.5	3.7	[email protected]
4.6	2.0	MEDIUM	`AV:L/AC:L/Au:N/C:P/I:P/A:P` Click to expand Access vector (AV:L) Requires local access to the target system. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:N) No authentication is required. Confidentiality impact (C:P) Partial confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:P) Partial availability impact.	3.9	6.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

5.7

3.0

MEDIUM

CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L Click to expand

Attack vector (AV:L): They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H): They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C): Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L): Some sensitive info could get out, but not a total data dump.
Integrity (I:L): Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L): Might cause slowdowns, glitches, or partial disruption—not a full brick.

1.5

3.7

[email protected]

4.6

2.0

MEDIUM

AV:L/AC:L/Au:N/C:P/I:P/A:P Click to expand

Access vector (AV:L): Requires local access to the target system.
Access complexity (AC:L): Exploitation conditions are straightforward and predictable.
Authentication (AU:N): No authentication is required.
Confidentiality impact (C:P): Partial confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:P): Partial availability impact.

3.9

6.4

[email protected]

Affected software / configurations for CVE-2017-12339

Vendor	Product	Version	Raw CPE
cisco	nx-os	7.0\(0\)hsk\(0.357\)	cpe:2.3:o:cisco:nx-os:7.0\(0\)hsk\(0.357\):::::::*
cisco	nx-os	8.0\(1\)	cpe:2.3:o:cisco:nx-os:8.0\(1\):::::::*
cisco	nx-os	8.1\(0\)bd\(0.20\)	cpe:2.3:o:cisco:nx-os:8.1\(0\)bd\(0.20\):::::::*
cisco	lan_switch_software	12.2\(1.107\)	cpe:2.3:o:cisco:lan_switch_software:12.2\(1.107\):::::::*

References for CVE-2017-12339

URL	Tags
http://www.securityfocus.com/bid/102198
http://www.securitytracker.com/id/1039938	Third Party Advisory VDB Entry
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20171129-nxos7	Vendor Advisory

URL

CVE-2017-12339

Exploit prediction scoring system (EPSS) score for CVE-2017-12339

Common vulnerability scoring system (CVSS) metrics for CVE-2017-12339

Weakness enumeration for CVE-2017-12339

Affected software / configurations for CVE-2017-12339

References for CVE-2017-12339