CVE-2019-1977 Cisco Nexus 9000 Series Fabric Switches ACI Mode Border Leaf Endpoint Learning Vulnerability
Unauthenticated remote attackers can cause denial of service on endpoints by exploiting improper endpoint learning in Cisco Nexus switches with specific configurations.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2019-1977?
CVE-2019-1977 is a medium-severity denial of service vulnerability in Cisco Nx-Os, published on 29 Aug 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability within the Endpoint Learning feature of Cisco Nexus 9000 Series Switches running in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an endpoint device in certain circumstances. The vulnerability is due to improper endpoint learning when packets are received on a specific port from outside the ACI fabric and destined to an endpoint located on a border leaf when Disable Remote Endpoint Learning has been enabled. This can result in a Remote (XR) entry being created for the impacted endpoint that will become stale if the endpoint migrates to a different port or leaf switch. This results in traffic not reaching the impacted endpoint until the Remote entry can be relearned by another mechanism.
Weakness: CWE-371
Which versions are affected by CVE-2019-1977?
It affects 1 product.
Products include Cisco Nx-Os.
How do I fix CVE-2019-1977?
No fix has been published for CVE-2019-1977 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2019-1977 being exploited?
There is no known exploitation of CVE-2019-1977 in the wild and no public exploit code.
Other vulnerabilities in Cisco Nx-Os
Sources
Also known as GHSA-3993-q22g-mw33.