Description

A vulnerability in the Internet Key Exchange version 2 (IKEv2) function of Cisco IOS XR Software could allow an unauthenticated, remote attacker to prevent an affected device from processing any control plane UDP packets. 

This vulnerability is due to improper handling of malformed IKEv2 packets. An attacker could exploit this vulnerability by sending malformed IKEv2 packets to an affected device. A successful exploit could allow the attacker to prevent the affected device from processing any control plane UDP packets, resulting in a denial of service (DoS) condition.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

Classification

CVE ID: CVE-2025-20209

CVSS Base Severity: HIGH

CVSS Base Score: 7.5

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

Affected Products

Vendor: Cisco

Product: Cisco IOS XR Software

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.09% (probability of being exploited)

EPSS Percentile: 22.87% (scored less or equal to compared to others)

EPSS Date: 2025-04-10 (when was this score calculated)

References

https://nvd.nist.gov/vuln/detail/CVE-2025-20209
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-xrike-9wYGpRGq
https://blog.apnic.net/2024/09/02/crafting-endless-as-paths-in-bgp/

Timeline