Improper input validation in Cisco Nx-Os Software
CVE-2020-3398
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 a BGP session to repeatedly reset, causing a partial denial of service (DoS) condition due to the BGP session being down. The vulnerability is due to incorrect parsing of a specific type of BGP MVPN update message. An attacker could exploit this vulnerability by sending this BGP MVPN update message to a targeted device. A successful exploit could allow the attacker to cause the BGP peer connections to reset, which could lead to BGP route instability and impact traffic. The incoming BGP MVPN update message is valid but is parsed incorrectly by the NX-OS device, which could send a corrupted BGP update to the configured BGP peer. 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.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
EPSS: 0.018 (77.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- psirt@cisco.com (x_refsource_CISCO, vendor-advisory, Vendor Advisory)
Frequently asked questions
- What is CVE-2020-3398?
- CVE-2020-3398 is a high-severity vulnerability in Cisco Nx-Os Software, classified under Improper Input Validation. CVSS score: 8.6/10. Published 2020-08-27.
- How severe is CVE-2020-3398?
- High severity. CVSS v3 base score is 8.6 out of 10.
- Is CVE-2020-3398 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.