Local Command Execution Vulnerability in Cisco IOS XR Software

CVE-2026-20040

What is CVE-2026-20040?

CVE-2026-20040 is a serious vulnerability found within Cisco's IOS XR Software, which is extensively used in network routing and telecommunications equipment. This software facilitates critical functions for internet service providers and large enterprises, including data routing, network management, and security operations. The identified vulnerability arises from insufficient validation of user inputs in specific command-line interface (CLI) commands. This flaw permits an authenticated attacker, possessing a low-privileged account, to execute arbitrary commands with root privileges on the device's underlying operating system. If exploited, this could lead to extensive control over the device, compromising network integrity and exposing sensitive information to unauthorized activities.

Potential impact of CVE-2026-20040

1. Privilege Escalation: The vulnerability allows an authenticated, low-privileged user to elevate their rights to root access. This type of privilege escalation can result in full administrative control over affected devices, enabling attackers to manipulate system configurations, deploy malicious software, or alter security settings.

2. Network Disruption: Given that Cisco IOS XR Software is pivotal for network management, exploiting this vulnerability can lead to service interruptions. An attacker could execute commands to reconfigure essential routing functions, leading to downtime or degraded performance, which could have catastrophic implications for uptime and service reliability.

3. Data Breach Risks: Once an attacker gains root access, they can potentially access sensitive data stored on or processed by the device. This access can lead to data exfiltration, exposing personal, financial, or corporate information, which could be utilized for malicious purposes or sold on illicit markets.

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