---
id: CVE-2025-20115
title: Cisco IOS XR Software Border Gateway Protocol Denial of Service Vulnerability
summary: "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.\r\n\r\nThis vulnerability is due to a …"
severity: high
cvss: 8.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H'
cvssSource: vendor
vendor: Cisco
product: Cisco IOS XR Software
affected:
  - ios_xr_software
published: '2025-03-12'
updated: '2025-03-12'
sourceUpdated: '2025-03-12T16:00:00+00:00'
source: CSAF
sourceUrl: >-
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-bgp-dos-O7stePhX
references:
  - url: >-
      https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-bgp-dos-O7stePhX
  - url: 'https://software.cisco.com'
tags:
  - csaf
  - vendor-advisory
  - cisco
  - exploit-available
epss: 0.00894
epssPercentile: 0.58185
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/gduma-phData/patch-CVE-2025-20115'
  checkedAt: '2026-10-07T08:10:58.648Z'
exploitAvailable: true
ingestedAt: '2026-10-07T08:10:21.957Z'
---

## Overview

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.

Cisco has released software updates that address this vulnerability. There is a workaround that addresses this vulnerability.



This advisory is part of the March 2025 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2025 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75548"].

## Vendor advisories

- **cisco-sa-iosxr-bgp-dos-O7stePhX** · Cisco · affected: Cisco IOS XR Software · updated 2025-03-12 · [advisory](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-bgp-dos-O7stePhX)

**Cisco IOS XR Software Border Gateway Protocol Confederation Denial of Service Vulnerability**. Released 2025-03-12.

Affected:

- Cisco IOS XR Software

## Remediation

Cisco has released software updates that address this vulnerability. https://software.cisco.com