Resource exhaustion in Cisco iOS Xr Software
CVE-2025-20209
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.005 (43.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 43.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.000
Affected products
- Cisco iOS Xr Software — versions 6.5.3, 6.6.1, 6.5.2
- Cisco iOS Xr — versions 6.5.1, 6.5.2, 6.5.3
- Cisco Ncs 1004
- Cisco Ncs 1010
- Cisco Ncs 1014
- Cisco Ncs 540l
Weakness classification (CWE)
References
- sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-… (Vendor Advisory)
- blog.apnic.net/2024/09/02/crafting-endless-as-paths-in-bgp/ (Not Applicable)
Frequently asked questions
- What is CVE-2025-20209?
- CVE-2025-20209 is a high-severity vulnerability in Cisco iOS Xr Software, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2025-03-12.
- How severe is CVE-2025-20209?
- High severity. CVSS v3 base score is 7.5 out of 10.