Cisco IOS XR CLI Local Authenticated Privilege Escalation via Argument Validation
CVE-2026-20040 Published on March 11, 2026
Cisco IOS XR Software CLI Privilege Escalation Vulnerability
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.
Vulnerability Analysis
CVE-2026-20040 is exploitable with local system access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Weakness Type
What is a Shell injection Vulnerability?
The software constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.
CVE-2026-20040 has been classified to as a Shell injection vulnerability or weakness.
Products Associated with CVE-2026-20040
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Affected Versions
Cisco IOS XR Software:- Version 6.5.3 is affected.
- Version 6.5.29 is affected.
- Version 6.5.1 is affected.
- Version 6.6.1 is affected.
- Version 6.5.2 is affected.
- Version 6.5.92 is affected.
- Version 6.5.15 is affected.
- Version 6.6.2 is affected.
- Version 7.0.1 is affected.
- Version 6.6.25 is affected.
- Version 6.5.26 is affected.
- Version 6.6.11 is affected.
- Version 6.5.25 is affected.
- Version 6.5.28 is affected.
- Version 6.5.93 is affected.
- Version 6.6.12 is affected.
- Version 6.5.90 is affected.
- Version 7.1.1 is affected.
- Version 7.0.90 is affected.
- Version 6.6.3 is affected.
- Version 6.7.1 is affected.
- Version 7.0.2 is affected.
- Version 7.1.15 is affected.
- Version 7.2.1 is affected.
- Version 7.1.2 is affected.
- Version 6.7.2 is affected.
- Version 7.0.11 is affected.
- Version 7.0.12 is affected.
- Version 7.0.14 is affected.
- Version 7.1.25 is affected.
- Version 6.6.4 is affected.
- Version 7.2.12 is affected.
- Version 7.3.1 is affected.
- Version 7.1.3 is affected.
- Version 6.7.3 is affected.
- Version 7.4.1 is affected.
- Version 7.2.2 is affected.
- Version 6.7.4 is affected.
- Version 6.5.31 is affected.
- Version 7.3.15 is affected.
- Version 7.3.16 is affected.
- Version 6.8.1 is affected.
- Version 7.4.15 is affected.
- Version 6.5.32 is affected.
- Version 7.3.2 is affected.
- Version 7.5.1 is affected.
- Version 7.4.16 is affected.
- Version 7.3.27 is affected.
- Version 7.6.1 is affected.
- Version 7.5.2 is affected.
- Version 7.8.1 is affected.
- Version 7.6.15 is affected.
- Version 7.5.12 is affected.
- Version 7.8.12 is affected.
- Version 7.3.3 is affected.
- Version 7.7.1 is affected.
- Version 6.8.2 is affected.
- Version 7.3.4 is affected.
- Version 7.4.2 is affected.
- Version 6.7.35 is affected.
- Version 6.9.1 is affected.
- Version 7.6.2 is affected.
- Version 7.5.3 is affected.
- Version 7.7.2 is affected.
- Version 6.9.2 is affected.
- Version 7.9.1 is affected.
- Version 7.10.1 is affected.
- Version 7.8.2 is affected.
- Version 7.5.4 is affected.
- Version 6.5.33 is affected.
- Version 7.8.22 is affected.
- Version 7.7.21 is affected.
- Version 7.9.2 is affected.
- Version 7.3.5 is affected.
- Version 7.5.5 is affected.
- Version 7.11.1 is affected.
- Version 7.9.21 is affected.
- Version 7.10.2 is affected.
- Version 24.1.1 is affected.
- Version 7.6.3 is affected.
- Version 7.3.6 is affected.
- Version 7.5.52 is affected.
- Version 7.11.2 is affected.
- Version 24.2.1 is affected.
- Version 24.1.2 is affected.
- Version 24.2.11 is affected.
- Version 24.3.1 is affected.
- Version 24.4.1 is affected.
- Version 24.2.2 is affected.
- Version 7.8.23 is affected.
- Version 7.11.21 is affected.
- Version 24.2.20 is affected.
- Version 24.3.2 is affected.
- Version 24.4.10 is affected.
- Version 6.5.35 is affected.
- Version 25.1.1 is affected.
- Version 24.4.2 is affected.
- Version 24.3.20 is affected.
- Version 24.4.15 is affected.
- Version 25.2.1 is affected.
- Version 6.5.351 is affected.
- Version 25.1.2 is affected.
- Version 24.3.30 is affected.
- Version 25.3.1 is affected.
- Version 6.5.352 is affected.
- Version 24.4.30 is affected.
- Version 24.2.21 is affected.
- Version 25.4.1 is affected.
- Version 25.2.2 is affected.
- Version 25.2.15 is affected.
- Version 7.2.0 is affected.
- Version 7.0.0 is affected.
- Version 25.2.30 is affected.
- Version 6.5.353 is affected.
- Version 25.1.30 is affected.
- Version 25.3.15 is affected.