CVE-2025-20340 Details
Description
A vulnerability in the Address Resolution Protocol (ARP) implementation of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to trigger a broadcast storm, leading to a denial of service (DoS) condition on an affected device. This vulnerability is due to how Cisco IOS XR Software processes a high, sustained rate of ARP traffic hitting the management interface. Under certain conditions, an attacker could exploit this vulnerability by sending an excessive amount of traffic to the management interface of an affected device, overwhelming its ARP processing capabilities. A successful exploit could result in degraded device performance, loss of management connectivity, and complete unresponsiveness of the system, leading to a DoS condition.
A denial-of-service vulnerability has been identified in the Address Resolution Protocol (ARP) implementation of Cisco IOS XR Software. This issue allows an unauthenticated, adjacent attacker to trigger a broadcast storm, causing a DoS condition on the affected device. The vulnerability arises from the way Cisco IOS XR processes high volumes of ARP traffic on the management interface. An attacker could exploit this by sending excessive traffic, overwhelming the device's ARP processing capabilities. The result is degraded performance, loss of management connectivity, and complete unresponsiveness, leading to a DoS condition.
Cisco has released free software updates to address this vulnerability. Customers with service contracts should obtain these updates through their usual channels. For those without service contracts, contact the Cisco Technical Assistance Center (TAC) for assistance. Consult the Cisco IOS XR Software Security Advisory Bundled Publication for specific upgrade instructions.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Sep 10, 2025CISA-ADP
Assessed Sep 10, 2025References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-arp-storm-EjUU55yM | [email protected] | AdvisoryRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-400 | Uncontrolled Resource Consumption | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Cisco IOS XR | <= 7.11 <= 24.1 <= 24.3 <= 24.4 <= 25.1 <= 25.2 |
CPE
Remediation
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Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Sep 26, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Sep 10, 2025 | New CVE Received | [email protected] |