VulnerabilityModified

CVE-2020-3397

HIGH 8.6EPSS 1.81%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.81%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

A vulnerability in the Border Gateway Protocol (BGP) Multicast VPN (MVPN) implementation of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause an affected device to unexpectedly reload, resulting in a denial of service (DoS) condition. The vulnerability is due to incomplete input validation of a specific type of BGP MVPN update message. An attacker could exploit this vulnerability by sending this specific, valid BGP MVPN update message to a targeted device. A successful exploit could allow the attacker to cause one of the BGP-related routing applications to restart multiple times, leading to a system-level restart. Note: The Cisco implementation of BGP accepts incoming BGP traffic from only explicitly configured peers. To exploit this vulnerability, an attacker must send a specific BGP MVPN update message over an established TCP connection that appears to come from a trusted BGP peer. To do so, the attacker must obtain information about the BGP peers in the trusted network of the affected system.

CVSS 3.1: 8.6 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS: 1.81% probability · 78th percentile
Public exploits: None in Exploit-DB
CISA KEV: Not listed
Weakness: CWE-20
Affected: cisco/nx-os
Source: psirt@cisco.com

EPSS trend

EPSS 1.8% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.