What’s Vulnerable › Vulnerabilities

CVE-2023-20236

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-09-13 · updated 2026-06-17
• Weakness: CWE-347

Description

A vulnerability in the iPXE boot function of Cisco IOS XR software could allow an authenticated, local attacker to install an unverified software image on an affected device. This vulnerability is due to insufficient image verification. An attacker could exploit this vulnerability by manipulating the boot parameters for image verification during the iPXE boot process on an affected device. A successful exploit could allow the attacker to boot an unverified software image on the affected device.

Affected products

• Cisco IOS XR Software: before 7.10.1 — fixed in 7.10.1

How to fix

Upgrade to a fixed version: Cisco IOS XR Software 7.10.1. Check the vendor advisory for mitigations.

References

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-ipxe-sigbypass-pymfyqgB
• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-ipxe-sigbypass-pymfyqgB

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