CVE-2020-3479

Cisco IOS and IOS XE Software MP-BGP EVPN Denial of Service Vulnerability

HIGH

7.5

CVSS Score

Published: September 24, 2020 at 05:52 PM UTC

Updated: June 17, 2026 at 03:18 AM UTC

26 products affected across 1 vendorIOSIOS XeAsr 1002-x

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Severity

HIGH7.5

Exploit prediction

EPSS 1%

SSVC

No known exploit

Description

A vulnerability in the implementation of Multiprotocol Border Gateway Protocol (MP-BGP) for the Layer 2 VPN (L2VPN) Ethernet VPN (EVPN) address family in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to incorrect processing of Border Gateway Protocol (BGP) update messages that contain crafted EVPN attributes. An attacker could exploit this vulnerability by sending BGP update messages with specific, malformed attributes to an affected device. A successful exploit could allow the attacker to cause an affected device to crash, resulting in a DoS condition.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

IOS · Cisconpm

95%

All versions

cisco-1100-integrated-services-router (environment) · cisco-1101-integrated-services-router (environment) · cisco-1109-integrated-services-router (environment) · cisco-1111x-integrated-services-router (environment) · cisco-111x-integrated-services-router (environment) · cisco-1120-integrated-services-router (environment) · cisco-1160-integrated-services-router (environment) · cisco-4221-integrated-services-router (environment) · cisco-4321-integrated-services-router (environment) · cisco-4331-integrated-services-router (environment) · cisco-4351-integrated-services-router (environment) · cisco-4431-integrated-services-router (environment) · cisco-4451-x-integrated-services-router (environment) · cisco-4461-integrated-services-router (environment) · cisco-asr-1001-hx (environment) · cisco-asr-1001-x (environment) · cisco-asr-1002-hx (environment) · cisco-asr-1002-x (environment) · cisco-asr-1004 (environment) · cisco-asr-1006 (environment) · cisco-asr-1006-x (environment) · cisco-asr-1009-x (environment) · cisco-asr-1013 (environment) · cisco-cloud-services-router-1000v (environment)

IOS Xe · Cisco

95%

All versions

1100 Integrated Services Router · Ciscodevice

80%

All versions

1101 Integrated Services Router · Ciscodevice

80%

All versions

1109 Integrated Services Router · Ciscodevice

80%

All versions