Cisco Patches High-Severity IOS XR Vulnerabilities

Cisco on Wednesday released patches for three vulnerabilities in IOS XR software, as part of its September 2025 security advisory bundled publication. The flaws are tracked as CVE-2025-20248 (CVSS 6), CVE-2025-20340 (CVSS 7.4) and CVE-2025-20159 (CVSS 5.3). The first flaw could allow attackers to bypass image signature verification, potentially enabling unsigned files to be added to an ISO image and installed on a device, with Cisco noting the advisory’s severity was raised from medium to high due to the bypass.

The second issue affects ARP handling and could enable a DoS condition when adversaries send excessive ARP traffic to the management interface. The third vulnerability could let unauthenticated, remote attackers bypass ACLs for SSH, NetConf and gRPC by exploiting insufficient management interface ACL support. Cisco says it is not aware of these vulnerabilities being exploited in the wild, and users are advised to apply the patches promptly.