CVE-2021-0536
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 · uneditedIn dropFile of WiFiInstaller, there is a way to delete files accessible to CertInstaller due to a confused deputy. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-11Android ID: A-176756691
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 confidenceA confused deputy vulnerability in the WiFiInstaller's dropFile function allows a local attacker to delete files accessible to CertInstaller. Since the WiFiInstaller has elevated privileges that CertInstaller also uses, an attacker can exploit this to delete files they normally wouldn't have access to, potentially achieving local privilege escalation.
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= 11.0CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/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 checksWork through these to decide whether this CVE applies to you.
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Check Android versionRun 'adb shell getprop ro.build.version.release' or go to Settings > About Phone > Android versionAffected if The version shows 11.0 exactly (Android 11)
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Identify WiFiInstaller packageRun 'adb shell pm list packages | grep -i wifiinstaller' to find the packageAffected if A package containing 'wifiinstaller' is listed in the installed packages
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Verify CertInstaller presenceRun 'adb shell pm list packages | grep -i certinstaller' to confirm CertInstaller is installedAffected if CertInstaller package exists on the device (required for the attack path)
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Check for vulnerable dropFile functionRun 'adb shell dumpsys package <wifiinstaller_package>' to inspect component exportsAffected if The WiFiInstaller exports a dropFile function that is accessible to other apps
A device is affected if it runs Android 11.0 and contains the WiFiInstaller component with the vulnerable exported dropFile function accessible to local applications.
Generated from the published advisory. Verify against your own configuration.
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 dataApply the Android-11 security patch that addresses this vulnerability. The fix requires modifying WiFiInstaller's file handling logic to properly validate and restrict file operations to prevent cross-component file access.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-0536 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-0536 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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
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