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

published 2020-09-24 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-24750

cvss: 6.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 1.1%; EPSS 1.1% chance of exploitation in 30 days, percentile 65%
public exploits: 0; none known

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.

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 23 mo ago (2024-11-13)

Exploit prediction

1.10% chance of exploitation in the next 30 days, higher than 65% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.1	CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:N/I:N/A:H
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD	2.0	7.8	AV:N/AC:L/Au:N/C:N/I:N/A:C

Affected products

Cisco Cisco IOS 15.2(5)E1

Classification

Weakness

CWE-20 Improper Input Validation
CWE-400 Uncontrolled Resource Consumption

Technology feeds

Cisco IOS rss critical rss

References

tools.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-ios-bgp-evpn-dos-LNfYJxfF
vendor-advisory

Sources

CVE List CVE-2020-3479
NVD CVE-2020-3479

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Summary