Denial of service in Cisco IOS XR Software

Published: 2020-08-06
Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE ID CVE-2020-3449
Exploitation vector Network
Public exploit N/A
Vulnerable software
Cisco IOS XR
Operating systems & Components / Operating system

Vendor Cisco Systems, Inc

Security Advisory

This security advisory describes one medium risk vulnerability.

1) Infinite loop

Risk: Medium

CVSSv3: 6.5 [CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C] [PCI]

CVE-ID: CVE-2020-3449

CWE-ID: CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')

Exploit availability: No


The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to an incorrect calculation of lexicographical order when displaying additional path information within the Border Gateway Protocol (BGP) additional paths feature. A remote attacker can send a specific BGP update from a BGP neighbor peer session of an affected device, consume all available system resources and cause denial of service conditions.


Install updates from vendor's website.

Vulnerable software versions

Cisco IOS XR: -, 7.1.2

CPE External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.