CVE-2024-20456

Unsigned image loading via manipulable boot configuration

Published Jul 10, 2024 · Updated Aug 1, 2024

Secure Boot bypass in Cisco IOS XR Software 24.2.1 allows local users with root-system privileges to load unverified software. A software build-process error leaves boot configuration options able to bypass integrity checks that enforce Cisco-signed images. Root-system access to an affected physical router is required; successful manipulation controls boot configuration and alters the running system's security properties.

CVSS severity6.7
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Secure Boot bypass in Cisco IOS XR Software 24.2.1 allows local users with root-system privileges to load unverified software. A software build-process error leaves boot configuration options able to bypass integrity checks that enforce Cisco-signed images. Root-system access to an affected physical router is required; successful manipulation controls boot configuration and alters the running system's security properties.

The record

CVE
CVE-2024-20456
Published
Jul 10, 2024
Updated
Aug 1, 2024
Vendor
ClamAV
Product
Cisco IOS XR Software
Classifications
CWE-732, T1542
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jul 10, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 1, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=24.2.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

ClamAV · Cisco IOS XR Softwareversion=24.2.1

Published CVSS scores

6.7CiscoCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-732Incorrect Permission Assignment for Critical Resource
T1542Pre-OS Boot

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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