CVE-2021-38785
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 · uneditedThere is a NULL pointer deference in the Allwinner R818 SoC Android Q SDK V1.0 camera driver /dev/cedar_dev that could use the ioctl cmd IOCTL_GET_IOMMU_ADDR to cause a system crash.
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 NULL pointer dereference vulnerability exists in the Allwinner R818 SoC Android Q SDK V1.0 camera driver (cedar_dev). When the ioctl command IOCTL_GET_IOMMU_ADDR is issued, the driver attempts to dereference a NULL pointer without proper validation, causing a system crash.
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= 1.0CVSS 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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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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Identify the SoC platformCheck the system-on-chip in use by reviewing /proc/cpuinfo, /sys/class/socinfo, or device tree bindings. Look for 'R818' or 'Allwinner R818' in the output.Affected if The device is not using an Allwinner R818 SoC, then it is not affected.
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Verify the Android Q SDK versionCheck the SDK version by examining system properties (getprop ro.build.version.sdk), boot image, or firmware metadata. Look for version 1.0.Affected if The SDK version is not exactly 1.0 (Android Q SDK), the system is not affected.
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Confirm cedar_dev driver presenceCheck if the cedar_dev camera driver is loaded or present on the system. Look for /dev/cedar_dev, or check lsmod for cedar-related modules, or review /sys/module/ for cedar drivers.Affected if The cedar_dev driver is not present on the system, the vulnerability cannot be triggered.
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Check for IOCTL interface accessVerify if the IOCTL_GET_IOMMU_ADDR command handler exists in the cedar_dev driver by examining driver source code if available, or by checking if user-space applications can issue ioctl calls to /dev/cedar_dev.Affected if The IOCTL_GET_IOMMU_ADDR ioctl path is not accessible or implemented, the NULL dereference cannot be triggered.
A system is affected only if it runs on an Allwinner R818 SoC with Android Q SDK version 1.0, has the cedar_dev driver present, and exposes the IOCTL_GET_IOMMU_ADDR interface for triggering the NULL pointer dereference.
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 dataRemediate by updating to a patched SDK version if available, or by modifying the driver to add proper NULL pointer validation before dereferencing in the IOCTL_GET_IOMMU_ADDR handler.
- Consultation4.0 h
- Implementation6.0 h
- Testing12.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,752.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-38785 — 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-2021-38785 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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