CVE-2020-3398

mediumpriority · track · 35EPSS 0.018 · 79 %ileEURUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
1.82% (79th) EPSS
CVSS 4.3 · medium
Is it mine?
59 products
Check your exposure
Who says so?
4 sources
cnnvd · enisa_euvd · fstec_bdu · cisco_csaf

EPSS · scored 2026-10-26

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.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

02

cvss

Technical severity, 0–10. One row per scoring source.

8.6
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.3–8.6

v2.04.3mediumAV:N/AC:M/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 8.6 · impact 2.9
v3.18.6highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 4
v3.08.6highCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · ENISA EU
v3.08.6highCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · psirt@cisco.com USexploitability 3.9 · impact 4
v3.08.6highCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · Cisco PSIRT US
v3.18.6highAV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU
v3.17.9highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-20USprimaryCWE-20US
05

affected products (59)

Products and version ranges known to be affected.

showing 20 of 59
06

advisories (1)

Vendor and ecosystem advisories describing this.

  • cisco-sa-nxosbgp-mvpn-dos-K8kbCrJpCisco NX-OS Software Border Gateway Protocol Multicast VPN Session Denial of Service Vulnerability2020-08-26csaf · cisco_csafUS

    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. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is part of the August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication, which includes seven Cisco Security Advisories that describe seven vulnerabilities. For a complete list of the advisories and links to them, see Cisco Event Response: August 2020 Cisco FXOS and NX-OS Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-74239"].

07

also known as (4)

Other names and identifiers for this entity.

08

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bducisco_csafNVDCVE.orgMITRE
published 2020-08-27modified 2026-06-17
10

references (8)

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan