CVE-2017-12340

CVE-2017-12340 is a medium-severity vulnerability in Cisco Nx-os with a CVSS 3.x base score of 4.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-116.

Key facts

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.

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?
CVE-2017-12340 has a CVSS 3.x base score of 4.2, rated medium severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
Is CVE-2017-12340 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-12340?
CVE-2017-12340 affects Cisco Nx-os. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2017-12340?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2017-12340 published?
CVE-2017-12340 was published on 2017-11-30 and last updated on 2026-06-17.

References

Affected products (1)

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