Buffer overflow in Cisco iOS Xr Software
CVE-2025-20115
A vulnerability in confederation implementation for the Border Gateway Protocol (BGP) in Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to a memory corruption that occurs when a BGP update is created with an AS_CONFED_SEQUENCE attribute that has 255 autonomous system numbers (AS numbers). An attacker could exploit this vulnerability by sending a crafted BGP update message, or the network could be designed in such a manner that the AS_CONFED_SEQUENCE attribute grows to 255 AS numbers or more. A successful exploit could allow the attacker to cause memory corruption, which may cause the BGP process to restart, resulting in a DoS condition. To exploit this vulnerability, an attacker must control a BGP confederation speaker within the same autonomous system as the victim, or the network must be designed in such a manner that the AS_CONFED_SEQUENCE attribute grows to 255 AS numbers or more.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.009 (59.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 60th percentile — 59.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: +0.000
Affected products
- Cisco iOS Xr Software — versions 6.5.3, 6.5.29, 6.5.1
- Cisco iOS Xr — versions 6.5.1, 6.5.2, 6.5.3
Weakness classification (CWE)
Public proof-of-concept exploits
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/ (Third Party Advisory)
Frequently asked questions
- What is CVE-2025-20115?
- CVE-2025-20115 is a high-severity vulnerability in Cisco iOS Xr Software, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 8.6/10. Published 2025-03-12.
- How severe is CVE-2025-20115?
- High severity. CVSS v3 base score is 8.6 out of 10.
- Is CVE-2025-20115 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.