Is CVE-2026-20040 actively exploited?

No active exploitation of CVE-2026-20040 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-20040 be exploited remotely?

No. CVE-2026-20040 requires local access to exploit.

What is the CVSS score of CVE-2026-20040?

CVE-2026-20040 has a CVSS score of 8.8 (HIGH).

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HIGH

CVE-2026-20040

CWE-78Published: March 11, 2026· Updated: Mar 12, 2026

8.8

CVSS v3.1

EPSS:0.03%probability of exploitation in 30 daysPercentile:10.0th

Official Description

A vulnerability in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to execute arbitrary commands as root on the underlying operating system of an affected device.

This vulnerability is due to insufficient validation of user arguments that are passed to specific CLI commands. An attacker with a low-privileged account could exploit this vulnerability by using crafted commands at the prompt. A successful exploit could allow the attacker to elevate privileges to root and execute arbitrary commands on the underlying operating system.

NVD Source

Technical Analysis

CVE-2026-20040 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 8.8.

The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.