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AndroidOperating system · Google

CVE-2018-21052

CRITICAL · 9.8 CVSS v3.1 Published 2020-04-08
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An issue was discovered on Samsung mobile devices with N(7.x) and O(8.X) (Exynos chipsets) software. There is incorrect usage of shared memory in the vaultkeeper Trustlet, leading to arbitrary code execution. The Samsung ID is SVE-2018-12855 (October 2018).

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

This vulnerability exists in the vaultkeeper Trustlet (a Trusted Execution Environment component) on Samsung mobile devices running Android N (7.x) and O (8.X) with Exynos chipsets. The issue involves incorrect usage of shared memory within this secure component, which can be exploited to achieve arbitrary code execution at the TEE privilege level.

MitigationApply the Samsung security patch SVE-2018-12855 (October 2018) or later. Users should update their devices to the latest Samsung security patch level to receive the fix for this vulnerability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
AndroidOperating system
Affected:= 7.0= 7.1.0= 7.1.1= 7.1.2= 8.0= 8.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Android version is affected
    Go to Settings > About Phone > Android version. Confirm the version is 7.0, 7.1.0, 7.1.1, 7.1.2, 8.0, or 8.1
    Affected if Android version matches one of these exact versions (7.0, 7.1.x, 8.0, 8.1)
  2. Confirm device is Samsung with Exynos chipset
    Check the device model in Settings > About Phone > Model number. Research whether that specific model uses an Exynos chipset (typically identified by Exynos model numbers in the processor/soc specifications)
    Affected if Device is a Samsung model with an Exynos processor variant
  3. Check for vaultkeeper Trustlet presence
    This requires accessing TEE debug information via specialized tools or reviewing device firmware dumps for the vaultkeeper trustlet binary. On affected devices, this component is typically located in the TEE partition and is loaded at boot.
    Affected if The vaultkeeper Trustlet is present and active on the device
  4. Verify security patch level
    Go to Settings > About Phone > Security patch level. Compare the date against the October 2018 Samsung security patch (SVE-2018-12855)
    Affected if Security patch level is earlier than October 2018 or the patch date is not displayed

The device is affected if it is a Samsung device with an Exynos chipset running Android 7.x or 8.x and the vaultkeeper Trustlet is present without the October 2018 or later security patch applied.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Samsung security patch SVE-2018-12855 (October 2018) or later. Users should update their devices to the latest Samsung security patch level to receive the fix for this vulnerability.

Recommended fix Moderate confidence

October 2018 security patch level or later for Exynos-powered Samsung devices running Android N (7.x) or O (8.x)

  1. 1. Navigate to Settings > About device on the Samsung device
  2. 2. Tap on Software update or System update
  3. 3. Select Download and install to check for and apply the latest security patch
  4. 4. Ensure the device updates to a security patch level dated October 2018 or later (SVE-2018-12855)
  5. 5. If available, update to the latest firmware version provided by Samsung for your specific device model
  6. 6. After update, verify the security patch level in Settings > About device > Software information > Security patch level
Caveat Users on older Android versions may need to accept the full OS upgrade to receive security patches; some older devices may no longer receive updates

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Android Scoped from the published advisory
  • Consultation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
8.0 hours of engineering $1,360
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-21052 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data