CVE-2023-20064: Cisco IOS XR Software Bootloader Unauthenticated Information Disclosure Vulnerability

Severity: medium (CVSS 4.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-03-09 · updated 2026-06-17
Weakness: CWE-862

Description

A vulnerability in the GRand Unified Bootloader (GRUB) for Cisco IOS XR Software could allow an unauthenticated attacker with physical access to the device to view sensitive files on the console using the GRUB bootloader command line. This vulnerability is due to the inclusion of unnecessary commands within the GRUB environment that allow sensitive files to be viewed. An attacker could exploit this vulnerability by being connected to the console port of the Cisco IOS XR device when the device is power-cycled. A successful exploit could allow the attacker to view sensitive files that could be used to conduct additional attacks against the device.

Affected products

Cisco IOS XR Software: before 7.9.1; before 7.6.1; before 7.7.1 — fixed in 7.6.1, 7.7.1, 7.9.1

How to fix

Upgrade to a fixed version: Cisco IOS XR Software 7.6.1, 7.7.1, 7.9.1. Check the vendor advisory for mitigations.

References

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