CVE-2021-39729
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 the TitanM chip, there is a possible out of bounds write due to a missing bounds check. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-202006191References: 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 Google's TitanM secure chip (used in Pixel devices) allows an out-of-bounds write due to a missing bounds check. This enables local privilege escalation from System-level execution privileges, with no user interaction required. The flaw exists in the chip's firmware and requires a security patch update to remediate.
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.
-
Identify if the device has a TitanM chipCheck if the device is a Google Pixel 3, Pixel 3 XL, Pixel 4, Pixel 4 XL, Pixel 5, or Pixel 5a, as these are the models that contain the TitanM security chip. This can be verified via device settings under 'About phone' or by checking the product specifications.Affected if The device is a Pixel model containing TitanM and is running any Android version
-
Check the Android security patch levelNavigate to Settings > About phone > Android security patch level. This displays the date of the installed Android security update.Affected if The security patch level is earlier than the date when Google released the fix for CVE-2021-39729 (typically the February 2022 Android security update or later)
-
Verify the baseband and bootloader versionsAccess Settings > About phone to view the baseband version and bootloader version. These components may indicate whether firmware updates have been applied to the device.Affected if The baseband or bootloader versions are older and do not reflect the February 2022 or later security update bundle
A user is affected if they have a Pixel device with TitanM chip and their Android security patch level predates the February 2022 update that includes the TitanM firmware patch for this vulnerability.
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 include the TitanM firmware patch; this is a chip-level vulnerability requiring vendor-provided firmware update rather than application-level remediation.
- Consultation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-39729 — 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-2021-39729 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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
- No spam, self-promotion, credentials, or personal data