CVE-2019-16021: Cisco IOS XR Software BGP EVPN Denial of Service Vulnerabilities
First published: Wed Sep 23 2020(Updated: )
Multiple vulnerabilities in the implementation of 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. The vulnerabilities are due to incorrect processing of BGP update messages that contain crafted EVPN attributes. An attacker could exploit these vulnerabilities by sending BGP EVPN update messages with malformed attributes to be processed by an affected system. 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 traffic only from explicitly defined peers. To exploit these vulnerabilities, the malicious BGP update message would need to come from a configured, valid BGP peer, or would need to be injected by the attacker into the victim's BGP network on an existing, valid TCP connection to a BGP peer.
Credit: ykramarz@cisco.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Cisco IOS XR | =6.6.1 | |
| Cisco ASR 9000 | ||
| Cisco Asr 9010 | ||
| Cisco Asr 9904 | ||
| Cisco Asr 9910 | ||
| Cisco Asr 9912 | ||
| Cisco Asr 9922 | ||
| Cisco Ncs 540 | ||
| Cisco Ncs 5500 | ||
| Cisco Ncs 6000 | ||
| Cisco IOS XR | =6.6.2 | |
| Cisco ASR 9000 | ||
| Cisco Asr 9010 | ||
| Cisco Asr 9904 | ||
| Cisco Asr 9910 | ||
| Cisco Asr 9912 | ||
| Cisco Asr 9922 | ||
| Cisco Carrier Routing System | ||
| Cisco Ios Xrv 9000 | ||
| Cisco Ncs 5001 | ||
| Cisco Ncs 5002 | ||
| Cisco Ncs 5011 | ||
| Cisco IOS XR | =6.6.25 | |
| Cisco Ncs 540l | ||
| Cisco Ncs 560 | ||
| Cisco IOS XR | =7.0.1 | |
| Cisco Ncs 1001 | ||
| Cisco Ncs 1002 | ||
| Cisco Ncs 1004 |
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Reference Links
Frequently Asked Questions
What is CVE-2019-16021?
CVE-2019-16021 is a vulnerability in the implementation of Border Gateway Protocol (BGP) Ethernet VPN (EVPN) functionality in Cisco IOS XR Software.
What is the severity of CVE-2019-16021?
CVE-2019-16021 has a severity rating of 7.5 (high).
How can an unauthenticated attacker exploit CVE-2019-16021?
An unauthenticated attacker can exploit CVE-2019-16021 by sending specially crafted BGP update messages, leading to a denial of service (DoS) condition.
Which versions of Cisco IOS XR Software are affected by CVE-2019-16021?
Versions 6.6.1, 6.6.2, and 6.6.25 of Cisco IOS XR Software are affected by CVE-2019-16021.
How can I fix CVE-2019-16021?
To fix CVE-2019-16021, Cisco IOS XR Software users should upgrade to a fixed software release.
- collector/nvd-index
- agent/type
- agent/softwarecombine
- collector/mitre-cve
- source/MITRE
- agent/references
- agent/tags
- agent/author
- agent/description
- agent/last-modified-date
- agent/severity
- agent/weakness
- agent/title
- agent/event
- agent/first-publish-date
- vendor/cisco
- canonical/cisco ios xr
- version/cisco ios xr/6.6.1
- canonical/cisco asr 9000
- canonical/cisco asr 9010
- canonical/cisco asr 9904
- canonical/cisco asr 9910
- canonical/cisco asr 9912
- canonical/cisco asr 9922
- canonical/cisco ncs 540
- canonical/cisco ncs 5500
- canonical/cisco ncs 6000
- version/cisco ios xr/6.6.2
- canonical/cisco carrier routing system
- canonical/cisco ios xrv 9000
- canonical/cisco ncs 5001
- canonical/cisco ncs 5002
- canonical/cisco ncs 5011
- version/cisco ios xr/6.6.25
- canonical/cisco ncs 540l
- canonical/cisco ncs 560
- version/cisco ios xr/7.0.1
- canonical/cisco ncs 1001
- canonical/cisco ncs 1002
- canonical/cisco ncs 1004