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VulnerabilityAwaiting classification

CVE-2026-21046

HIGH · 8.4 CVSS v4.0 Published 2026-07-10
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
86/100
Remediation priority · High
Zero-click 6 weeks old

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
Time-of-check time-of-use race condition in fabricKeymaster trustlet prior to SMR Jul-2026 Release 1 allows local privileged attackers to execute arbitrary code.

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 · high confidence

A time-of-check time-of-use (TOCTOU) race condition in the fabricKeymaster trustlet allows local privileged attackers to execute arbitrary code. The vulnerability exists in Samsung's Knox security framework where a race condition between security checks and their use can be exploited by an attacker with local privileged access.

MitigationApply the Samsung SMR Jul-2026 Release 1 or later security update which contains the patch for fabricKeymaster. Organizations should inventory affected Samsung devices and ensure timely deployment of security patches.

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

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
Local
Complexity
Low
Privileges
High
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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. Identify Samsung device with Knox framework
    Check device model and confirm it is a Samsung device running the Knox security framework. On Android, go to Settings > About Phone > Software Information, or check for Knox-related apps in Settings > Apps.
    Affected if The device is a Samsung Android device with Knox security framework installed.
  2. Verify fabricKeymaster trustlet presence
    Check for the existence of the fabricKeymaster trustlet on the device. This is typically found in the /vendor or /system partition. Use ADB to run: 'ls -la /vendor/lib/hw/' or check for files containing 'fabricKeymaster' in the trustlet directory.
    Affected if The fabricKeymaster trustlet is present on the device, indicating the vulnerable component exists.
  3. Check Android security patch level
    Navigate to Settings > About Phone > Software Information > Security patch level, or use ADB command: 'adb shell getprop ro.build.version.security_patch'. This displays the installed security update date.
    Affected if The security patch level is earlier than July 2026 (SMR Jul-2026 Release 1), meaning the patch is not applied.
  4. Confirm Knox version
    Open Samsung Knox settings (Settings > Security and privacy > Knox) or check Knox version via ADB: 'adb shell dumpsys package com.sec.knox.seandroid' to identify the Knox version and configuration.
    Affected if Knox version is present and the security patch level is below the patched release.
  5. Assess local privileged access exposure
    Review device configuration for indicators of local privileged access. Check if the device is rooted, has custom firmware, or if untrusted apps have elevated privileges. Use ADB to check: 'adb shell su -c id' or review root management status in Knox settings.
    Affected if The device has local privileged access exposure, creating the condition where exploitation is possible per the TOCTOU attack vector.

A Samsung device with the Knox framework and fabricKeymaster trustlet present is affected if its security patch level predates the July 2026 SMR release and the device has local privileged access exposure.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Samsung SMR Jul-2026 Release 1 or later security update which contains the patch for fabricKeymaster. Organizations should inventory affected Samsung devices and ensure timely deployment of security patches.

Have this fixed Scoped from the published advisory
  • Consultation8.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,920
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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-2026-21046 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