CVE-2026-20171

Published: Mag 20, 2026 Last Modified: Mag 20, 2026
ExploitDB:
Other exploit source:
Google Dorks:
MEDIUM 6,8
Source: [email protected]
Attack Vector: network
Attack Complexity: high
Privileges Required: none
User Interaction: none
Scope: changed
Confidentiality: none
Integrity: none
Availability: high

Description

AI Translation Available

A vulnerability in the Border Gateway Protocol (BGP) enforce-first-as feature of Cisco Nexus 3000 Series Switches and Cisco Nexus 9000 Series Switches in standalone NX-OS mode could allow an unauthenticated, remote attacker to trigger BGP peer flaps, resulting in a denial of service (DoS) condition.

This vulnerability is due to incorrect parsing of a transitive BGP attribute. An attacker could exploit this vulnerability by sending a crafted BGP update through an established BGP peer session. If the update propagates to an affected device, it could cause the device to drop the BGP session and flap with the BGP peer that is forwarding this update, resulting in a DoS condition.

670

Always-Incorrect Control Flow Implementation

Draft
Abstraction: Class Structure: Simple
Common Consequences
Security Scopes Affected:
Other
Potential Impacts:
Other Alter Execution Logic
Applicable Platforms
All platforms may be affected
View CWE Details
https://sec.cloudapps.cisco.com/security/center/content/Cis…
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/c…