CVE-2021-38784
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 dereference in the syscall open_exec function of Allwinner R818 SoC Android Q SDK V1.0 that could executable a malicious file 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 · high confidenceA NULL pointer dereference vulnerability exists in the syscall open_exec function of Allwinner R818 SoC Android Q SDK V1.0. An attacker can exploit this by executing a malicious file, causing the NULL pointer to be dereferenced and resulting in a system crash (denial of service).
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 hardware in useCheck /proc/cpuinfo, /sys/class/socinfo, or device tree files (e.g., /proc/device-tree/compatible) to identify the system-on-chip model. For R818, look for 'sun8i' or 'r818' in the output.Affected if The system is not using an Allwinner R818 SoC, then the vulnerability does not apply.
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Determine the Android SDK versionCheck /system/build.prop for 'ro.build.version.sdk' and 'ro.build.version.release', or check the Allwinner-specific SDK version file if present in /vendor or /system. The affected version is specifically SDK V1.0.Affected if The SDK version is not exactly 1.0, the specific vulnerability may not be present.
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Verify the kernel supports the open_exec syscallInspect the kernel configuration (config.gz in /proc or /boot/config-*) for CONFIG_BINFMT_ELF or other binary format handlers. The open_exec function is part of the kernel's binfmt mechanism for executing files.Affected if The kernel does not include binary execution support, the attack surface may not exist.
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Check if user-space binary execution is enabledReview whether /proc/sys/kernel/core_pattern exists and if core dumps are enabled, or verify that the exec system call path is accessible. The vulnerability triggers when open_exec processes a file.Affected if Binary execution is disabled or restricted at the kernel level, exploitation may not be possible.
You are affected if your device uses an Allwinner R818 SoC with Android Q SDK version 1.0 and supports file execution through the open_exec syscall.
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 dataImplement proper NULL pointer validation in the open_exec function before dereferencing, ensuring all pointers are validated before use. Additionally, apply input validation on files being executed to prevent malicious file processing.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 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 $5,888.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-38784 — 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-2021-38784 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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