CVE-2022-20377
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 TBD of keymaster_ipc.cpp, there is a possible to force gatekeeper, fingerprint, and faceauth to use a known HMAC key. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-222339795References: N/A
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 confidenceA vulnerability in the keymaster IPC layer allows a local attacker to force gatekeeper, fingerprint, and faceauth components to use a known HMAC key, enabling authentication bypass and local privilege escalation without user interaction.
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 dataall versionsCVSS 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
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:H/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 security patch levelGo to Settings > About Phone > Android version or run 'getprop ro.build.version.security_patch' via ADB shell to see the installed security patch dateAffected if The security patch level is earlier than September 2022, as this vulnerability was addressed in that month's Android security update
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Verify keymaster module statusRun 'getprop ro.keymaster.*' or check /vendor/etc/init/android.hardware.keymaster* service status via ADB to see if the keymaster hardware abstraction layer is runningAffected if Keymaster is present and the IPC communication layer has not been patched; the flaw exists in the IPC layer between keymaster and authentication components
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Confirm authentication components are presentCheck for gatekeeper, fingerprint, and faceauth HAL services by running 'ls /vendor/etc/init/android.hardware.gatekeeper*' and similar paths, or via 'getprop | grep gatekeeper'Affected if Any of these authentication components (gatekeeper, fingerprint, faceauth) are enabled and configured to use keymaster for HMAC-based authentication operations
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Check for known HMAC key exposureReview system logs with 'logcat -d | grep keymaster' or dmesg for any messages indicating HMAC key derivation or reuse across sessions. Also check if keymaster allows exporting or deriving HMAC keys without proper isolationAffected if The IPC layer permits a local process to influence which HMAC key is used for authentication operations, allowing a known key to be substituted
A device is affected if it runs an Android version without the September 2022 or later security patch and has keymaster-based authentication (gatekeeper, fingerprint, or faceauth) enabled, since the unpatched IPC layer allows forcing use of a known HMAC key for authentication bypass.
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 Android security updates that address this keymaster IPC vulnerability; this is a system-level flaw requiring vendor/patch-level remediation.
- Consultation8.0 h
- Implementation20.0 h
- Testing16.0 h
- Review / QA8.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $14,464.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2022-20377 — 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-2022-20377 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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- Version or environment caveats, and links to real fixes
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