CVE-2021-0929
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 ion_dma_buf_end_cpu_access and related functions of ion.c, there is a possible way to corrupt memory due to a use after free. 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-187527909References: Upstream kernel
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 use-after-free vulnerability exists in ion_dma_buf_end_cpu_access and related functions within the ION (Ion Memory Manager) subsystem in the Android kernel. The vulnerability allows a local attacker to corrupt memory by accessing freed memory regions, potentially achieving local privilege escalation without requiring additional execution privileges or 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
- 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.
-
Confirm Android environmentRun 'uname -a' or check /proc/version to verify the system is running an Android kernelAffected if The system is running a Google Android kernel (the vulnerability exists only in Android kernels)
-
Verify ION subsystem is presentCheck for ION debugfs entries: 'ls /sys/kernel/debug/ion/' or check kernel config for CONFIG_ION=y or CONFIG_ION=mAffected if The ION Memory Manager is compiled into the kernel or loaded as a module - without ION, the vulnerable code path does not exist
-
Confirm ION is actively usedCheck /sys/kernel/debug/ion/ion_mm_heap0 or list active heaps: 'cat /sys/kernel/debug/ion/heaps'Affected if At least one ION heap is created and active - the vulnerability triggers in ion_dma_buf_end_cpu_access when CPU access to DMA buffers ends
-
Identify kernel patch statusCheck 'getprop ro.build.version.security_patch' for Android security patch level, or compare 'uname -r' output against vendor release notes for the A-187527909 fixAffected if The security patch level is earlier than the month the A-187527909 fix was released, meaning the use-after-free patch has not been applied
A user is affected if the device runs an Android kernel with the ION subsystem enabled and the A-187527909 patch has not been applied to address the use-after-free in ion_dma_buf_end_cpu_access.
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 upstream kernel patch for A-187527909 to fix the use-after-free condition in the ION subsystem. For Android devices, this requires updating to a kernel version that includes the vendor security patch containing this fix.
- Consultation4.0 h
- Implementation8.0 h
- Testing12.0 h
- Review / QA6.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,192.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-0929 — 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-2021-0929 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