CVE-2018-21070

Secure Boot bypass via unchecked system image

Published Apr 8, 2020 · Updated Aug 5, 2024

Improper integrity validation in Samsung mobile devices on Android 7.x and 8.0 allows local users to bypass Secure Boot. The MSM8998 and SDM845 bootloader verification path accepts a specially crafted system image without validating its integrity before loading it. Samsung states that root privilege is required to reach the flaw, limiting it to post-compromise Secure Boot bypass rather than initial privilege acquisition.

CVSS severity8.4
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper integrity validation in Samsung mobile devices on Android 7.x and 8.0 allows local users to bypass Secure Boot. The MSM8998 and SDM845 bootloader verification path accepts a specially crafted system image without validating its integrity before loading it. Samsung states that root privilege is required to reach the flaw, limiting it to post-compromise Secure Boot bypass rather than initial privilege acquisition.

The record

CVE
CVE-2018-21070
Published
Apr 8, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-354, T1601
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Apr 8, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.2NIST NVDAV:L/AC:L/Au:N/C:C/I:C/A:C
8.4NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

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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-354Improper Validation of Integrity Check Value
T1601Modify System Image

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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