Ethical Hacking News
Cisco has addressed multiple high-severity vulnerabilities in its IOS XR software, which can enable image bypass and trigger denial-of-service (DoS) conditions on affected devices. The most severe of these vulnerabilities is a high-severity issue that resides in the Address Resolution Protocol (ARP) implementation of Cisco IOS XR Software.
Cisco Systems has identified multiple high-severity vulnerabilities in its IOS XR software. The most severe vulnerability, CVE-2025-20340, can enable image bypass and trigger denial-of-service (DoS) conditions on affected devices. Unauthenticated, adjacent attackers can exploit the vulnerability by sending excessive traffic to a device's management interface. A high-severity issue in the IOS XR installation process allows attackers to bypass image signature verification. Attackers with root-system privileges on affected devices can exploit this vulnerability by modifying the .iso file and installing it. A medium-severity flaw lets remote attackers bypass ACLs for SSH, NetConf, and gRPC due to missing ACL support in the management interface.
Cisco Systems has recently addressed multiple high-severity vulnerabilities in its IOS XR software, which can enable image bypass and trigger denial-of-service (DoS) conditions on affected devices. This is part of the company's semiannual Software Security Advisory Bundled Publication published on September 10, 2025.
The vulnerabilities identified by Cisco are tracked as CVE-2025-20340, CVE-2025-20248, and CVE-2025-20159, with security impact ratings of High, Medium, and High respectively. The most severe of these vulnerabilities is a high-severity issue, tracked as CVE-2025-20340, that resides in the Address Resolution Protocol (ARP) implementation of Cisco IOS XR Software.
According to Cisco, an unauthenticated, adjacent attacker can exploit this vulnerability by sending an excessive amount of traffic to the management interface of an affected device, overwhelming its ARP processing capabilities. This can result in degraded device performance, loss of management connectivity, and complete unresponsiveness of the system, leading to a DoS condition.
The first of the bugs is a high-severity issue in the IOS XR installation process that could allow attackers to bypass image signature verification. Successful exploitation of this flaw, Cisco explains, could lead to unsigned files being added to an ISO image, which could then be installed and activated on a device.
Because of the potential bypass of the image verification process, Cisco has raised the security impact rating of the advisory from medium to high. This means that attackers with root-system privileges on the affected device can exploit this vulnerability by modifying contents of the .iso file and then installing and activating it on the device.
The second vulnerability addressed by Cisco is a medium-severity flaw tracked as CVE-2025-20159, which lets remote attackers bypass ACLs for SSH, NetConf, and gRPC due to missing ACL support in the management interface.
Cisco has emphasized that it is not aware of any attacks in the wild exploiting one of these vulnerabilities. However, it is essential for network administrators and device owners to take immediate action to patch their devices with the latest security updates.
Related Information:
https://www.ethicalhackingnews.com/articles/Cisco-Addresses-Multiple-High-Severity-Vulnerabilities-in-IOS-XR-Software-ehn.shtml
https://securityaffairs.com/182144/security/cisco-fixes-high-severity-ios-xr-flaws-enabling-image-bypass-and-dos.html
https://nvd.nist.gov/vuln/detail/CVE-2025-20340
https://www.cvedetails.com/cve/CVE-2025-20340/
https://nvd.nist.gov/vuln/detail/CVE-2025-20248
https://www.cvedetails.com/cve/CVE-2025-20248/
https://nvd.nist.gov/vuln/detail/CVE-2025-20159
https://www.cvedetails.com/cve/CVE-2025-20159/
Published: Fri Sep 12 10:12:38 2025 by llama3.2 3B Q4_K_M
