CVE-2021-1440: A vulnerability in the implementation of the Resource Public Key Infrastructure (RPKI) feature of Cisco IOS XR Software could allow an unauthenti...

Description

A vulnerability in the implementation of the Resource Public Key Infrastructure (RPKI) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause the Border Gateway Protocol (BGP) process to crash, resulting in a denial of service (DoS) condition. This vulnerability is due to the incorrect handling of a specific RPKI to Router (RTR) Protocol packet header. An attacker could exploit this vulnerability by compromising the RPKI validator server and sending a specifically crafted RTR packet to an affected device. Alternatively, the attacker could use man-in-the-middle techniques to impersonate the RPKI validator server and send a specifically crafted RTR response packet over the established RTR TCP connection to the affected device. A successful exploit could allow the attacker to cause a DoS condition because the BGP process could constantly restart and BGP routing could become unstable.Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see .

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

0.77%

51.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-617

Affected Software

Vendor	Product	Versions
Cisco	Ios Xr	>= 4.3.0, < 7.3.1

References

Timeline

Published: Nov 18, 2024
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2021-1440?

A vulnerability in the implementation of the Resource Public Key Infrastructure (RPKI) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause the Border Gateway Protocol (BGP) process to crash, resulting in a denial of service (DoS) condition. This vulnerability is due to the incorrect handling of a specific RPKI to Router (RTR) Protocol packet header. An attacker could exploit this vulnerability by compromising the RPKI validator server and sending a specifically crafted RTR packet to an affected device. Alternatively, the attacker could use man-in-the-middle techniques to impersonate the RPKI validator server and send a specifically crafted RTR response packet over the established RTR TCP connection to the affected device. A successful exploit could allow the attacker to cause a DoS condition because the BGP process could constantly restart and BGP routing could become unstable.Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see .

How severe is CVE-2021-1440?

CVE-2021-1440 has a CVSS score of 6.8/10 (MEDIUM severity). The EPSS model estimates a 0.77% probability of exploitation in the next 30 days.

How do I fix CVE-2021-1440?

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.