CVE-2018-21063

Unauthorized Keymaster API access from trustlets

Published Apr 8, 2020 · Updated Aug 5, 2024

Access-control failure in Samsung Keymaster on Android 6.0 through 8.x Exynos devices allows attackers to access a protected tlApi. The TEE exposes one Keymaster tlApi to an unspecified trustlet without the access-control restriction needed to limit privileged API callers. Exploitation requires code executing as a trustlet on an affected Exynos device; Samsung has not disclosed which tlApi operations or downstream effects are exposed.

CVSS severity9.8
Critical
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Access-control failure in Samsung Keymaster on Android 6.0 through 8.x Exynos devices allows attackers to access a protected tlApi. The TEE exposes one Keymaster tlApi to an unspecified trustlet without the access-control restriction needed to limit privileged API callers. Exploitation requires code executing as a trustlet on an affected Exynos device; Samsung has not disclosed which tlApi operations or downstream effects are exposed.

The record

CVE
CVE-2018-21063
Published
Apr 8, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1068
Attack vector
local
Privileges
Unavailable

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 privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

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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