CVE-2019-1836 Path traversal in Cisco NX-OS Software for Nexus 9000 Series Fabric Switches ACI Mode
Authenticated local attackers can overwrite restricted system files via symbolic links in the CLI, potentially escalating privileges on Cisco Nexus switches.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2019-1836?
CVE-2019-1836 is a medium-severity path traversal vulnerability in Cisco Nx-Os, published on 3 May 2019. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A vulnerability in the system shell for Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode could allow an authenticated, local attacker to use symbolic links to overwrite system files. These system files may be sensitive and should not be overwritable by non-root users. The attacker would need valid device credentials. The vulnerability is due to incorrect symbolic link verification of directory paths when they are used in the system shell. An attacker could exploit this vulnerability by authenticating to the device and providing crafted user input to specific symbolic link CLI commands. Successful exploitation could allow the attacker to overwrite system files that should be restricted. This vulnerability has been fixed in software version 14.1(1i).
Which versions are affected by CVE-2019-1836?
It affects 1 product.
Products include Cisco Nx-Os.
How do I fix CVE-2019-1836?
No fix has been published for CVE-2019-1836 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2019-1836 being exploited?
There is no known exploitation of CVE-2019-1836 in the wild and no public exploit code.
Other vulnerabilities in Cisco Nx-Os
Sources
Also known as GHSA-3pmp-7vwx-87p3.