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AndroidOperating system · Google

CVE-2021-39684

HIGH · 7.8 CVSS v3.1 Published 2022-01-14
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
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
In target_init of gs101/abl/target/slider/target.c, there is a possible allocation of RWX memory due to a logic error in the code. 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-203250788References: 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 confidence

A logic error in target_init of gs101/abl/target/slider/target.c causes the allocation of RWX (Read-Write-Execute) memory, which violates the principle of least privilege. This memory protection weakness can be exploited for local privilege escalation without requiring additional user privileges.

MitigationFix the logic error in the target initialization code to ensure memory is allocated with appropriate protection flags (RX or RW, not RWX), following kernel security best practices for memory executable permissions.

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:all versions

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
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 checks

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

  1. Identify the chipset in use
    Determine if the device uses the gs101 (Google Tensor) chipset. This can be done via /proc/cpuinfo or by checking the device's hardware specifications. The vulnerability exists specifically in gs101 bootloader code.
    Affected if The device uses the gs101 chipset (Pixel 6, Pixel 6 Pro) - only these devices contain the affected target.c code in their ABL bootloader.
  2. Verify the bootloader component exists
    Attempt to read or inspect the bootloader partitions (ABL). On affected devices, the vulnerable code would be in gs101/abl/target/slider/target.c within the bootloader image. This typically requires root access or specialized tools like fastboot or a custom recovery.
    Affected if The device has the gs101 ABL bootloader present - this is where the logic error in target_init exists.
  3. Check for RWX memory allocation capability
    Analyze the target_init function in the bootloader binary for patterns indicating RWX (Read-Write-Execute) memory allocation. This requires disassembling or debugging the bootloader. Look for mmap or allocation calls with RWX protection flags (0x7 or PROT_READ|PROT_WRITE|PROT_EXEC).
    Affected if The target_init function allocates memory with RWX (0x7) protection flags instead of safer RX or RW flags.
  4. Confirm privilege escalation context
    This vulnerability enables local privilege escalation without additional user privileges. If the device has been compromised via privilege escalation with no initial user privileges required, this could be the attack vector.
    Affected if Local privilege escalation has occurred without any user-assisted steps or additional privileges.

The device is affected only if it uses the gs101 (Google Tensor) chipset and contains the vulnerable ABL bootloader code with the RWX memory allocation logic error in target_init.

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

Fix the logic error in the target initialization code to ensure memory is allocated with appropriate protection flags (RX or RW, not RWX), following kernel security best practices for memory executable permissions.

Fix this in Android Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
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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-2021-39684 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
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