CVE-2022-20758: A vulnerability in the implementation of the Border Gateway Protocol (BGP) Ethernet VPN (EVPN) functionality in Cisco IOS XR Software could allow an u...

Description

A vulnerability in the implementation of the Border Gateway Protocol (BGP) Ethernet VPN (EVPN) functionality in Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to the incorrect processing of a BGP update message that contains specific EVPN attributes. An attacker could exploit this vulnerability by sending a BGP update message that contains specific EVPN attributes. To exploit this vulnerability, an attacker must control a BGP speaker that has an established trusted peer connection to an affected device that is configured with the address family L2VPN EVPN to receive and process the update message. This vulnerability cannot be exploited by any data that is initiated by clients on the Layer 2 network or by peers that are not configured to accept the L2VPN EVPN address family. A successful exploit could allow the attacker to cause the BGP process to restart unexpectedly, resulting in a DoS condition. The Cisco implementation of BGP accepts incoming BGP updates only from explicitly defined peers. For this vulnerability to be exploited, the malicious BGP update message must either come from a configured, valid BGP peer or be injected by the attacker into the affected BGP network on an existing, valid TCP connection to a BGP peer.

Metrics

CVSS 3.1

6.8/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H

EPSS Probability

1.14%

62.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-399

Affected Software

Vendor	Product	Versions
Cisco	Ios Xr	< 6.8.2
Cisco	Ios Xr	>= 7.0, < 7.3.2
Cisco	Ios Xr	>= 7.4, < 7.4.2

References

Timeline

Published: Apr 15, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-20758?

A vulnerability in the implementation of the Border Gateway Protocol (BGP) Ethernet VPN (EVPN) functionality in Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to the incorrect processing of a BGP update message that contains specific EVPN attributes. An attacker could exploit this vulnerability by sending a BGP update message that contains specific EVPN attributes. To exploit this vulnerability, an attacker must control a BGP speaker that has an established trusted peer connection to an affected device that is configured with the address family L2VPN EVPN to receive and process the update message. This vulnerability cannot be exploited by any data that is initiated by clients on the Layer 2 network or by peers that are not configured to accept the L2VPN EVPN address family. A successful exploit could allow the attacker to cause the BGP process to restart unexpectedly, resulting in a DoS condition. The Cisco implementation of BGP accepts incoming BGP updates only from explicitly defined peers. For this vulnerability to be exploited, the malicious BGP update message must either come from a configured, valid BGP peer or be injected by the attacker into the affected BGP network on an existing, valid TCP connection to a BGP peer.

How severe is CVE-2022-20758?

CVE-2022-20758 has a CVSS score of 6.8/10 (MEDIUM severity). The EPSS model estimates a 1.14% probability of exploitation in the next 30 days.

How do I fix CVE-2022-20758?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.