{"id":87157,"date":"2026-07-09T21:37:32","date_gmt":"2026-07-09T21:37:32","guid":{"rendered":""},"modified":"-0001-11-30T00:00:00","modified_gmt":"-0001-11-30T00:00:00","slug":"cve-2025-20340-denial-of-service-vulnerability-in-cisco-ios-xr-software-s-arp-implementation","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-20340-denial-of-service-vulnerability-in-cisco-ios-xr-software-s-arp-implementation\/","title":{"rendered":"CVE-2025-20340: Denial of Service Vulnerability in Cisco IOS XR Software’s ARP Implementation<\/strong>"},"content":{"rendered":"

Overview<\/strong><\/p>\n

This report provides an in-depth analysis of the CVE-2025-20340 vulnerability. This cybersecurity vulnerability is found in the implementation of the Address Resolution Protocol (ARP) in Cisco IOS XR Software. If exploited, it could lead to a Denial of Service (DoS) condition on affected devices. This vulnerability has the potential to disrupt network infrastructure, which underlines the importance of its mitigation.<\/p>\n

Vulnerability Summary<\/strong><\/p>\n

CVE ID: CVE-2025-20340
\nSeverity: High (CVSS Score: 7.4)
\nAttack Vector: Network
\nPrivileges Required: None
\nUser Interaction: None
\nImpact: Potential system compromise or data leakage<\/p>\n

Affected Products<\/strong><\/p>\n

Product | Affected Versions<\/p>\n

Cisco IOS XR Software | All prior versions to the upcoming patch<\/p>\n

How the Exploit Works<\/strong><\/p>\n

The exploit takes advantage of a flaw within the ARP implementation in the Cisco IOS XR Software. The attacker, by sending an excessive amount of traffic to the management interface of an affected device, can overwhelm its ARP processing capabilities. This high, sustained rate of ARP traffic can trigger a broadcast storm, leading to a denial of service (DoS) condition. If successful, the exploit could result in degraded device performance, a loss of management connectivity, and complete unresponsiveness of the system.<\/p>\n

Conceptual Example Code<\/strong><\/p>\n

While the exact methodology of the exploit may vary, a conceptual example would involve flooding the network with ARP requests targeting the management interface of the device. This could be done using a tool capable of generating high volumes of network traffic, such as hping3. A conceptual command may look something like this:<\/p>\n

hping3 -i u1 --arp --rand-source target_IP<\/code><\/pre>\n
In this example, the “-i u1” option sends one packet per microsecond, “–arp” specifies the use of ARP, and “–rand-source” randomizes the source IP address, making it harder to block the attack. The “target_IP” would be the IP address of the target device’s management interface.<\/p>\n","protected":false},"excerpt":{"rendered":"
Overview This report provides an in-depth analysis of the CVE-2025-20340 vulnerability. This cybersecurity vulnerability is found in the implementation of the Address Resolution Protocol (ARP) in Cisco IOS XR Software. If exploited, it could lead to a Denial of Service (DoS) condition on affected devices. This vulnerability has the potential to disrupt network infrastructure, which […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[],"tags":[],"vendor":[],"product":[],"attack_vector":[],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-87157","post","type-post","status-publish","format-standard","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t