Cisco Patches High-Severity IOS XR Vulnerabilities

Cisco on Wednesday published its semiannual IOS XR software security advisory bundle, which includes three advisories detailing four high-severity vulnerabilities.

The most severe of these issues are CVE-2026-20040 and CVE-2026-20046 (CVSS score of 8.8), two bugs that could be exploited to execute arbitrary commands as root or gain administrative control of a device.

CVE-2026-20040 exists because user arguments passed to specific CLI commands are not sufficiently validated, allowing a low-privileged attacker to supply 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,” Cisco explains in its advisory.

CVE-2026-20046 impacts the task group assignment for a specific CLI command and exists because the command is incorrectly mapped to task groups within the source code.

This allows an unprivileged attacker to bypass the task group-based checks via CLI commands to elevate their privileges to ...