CVE-2023-21065
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 fdt_next_tag of fdt.c, there is a possible out of bounds write due to an integer overflow. 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-239630493References: 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 · high confidenceAn integer overflow in the fdt_next_tag function of the Flattened Device Tree (FDT) parsing code in the Android kernel can lead to an out-of-bounds write. This occurs when the tag length calculation overflows, causing memory corruption that can be exploited for local privilege escalation from System privileges.
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.
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Confirm Android kernel is in useRun 'uname -a' and check for 'android' or check /proc/version for Android-specific kernel markersAffected if System is not running an Android kernel (this vulnerability is Android-specific)
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Verify FDT/DTB support is enabledCheck kernel config for CONFIG_OF and CONFIG_FLATTED_DEVICE_TREE, or check if /sys/firmware/fdt or /boot/dtb exists and is usedAffected if FDT support is compiled into the kernel and the device uses Device Tree Blobs (common in Android boot)
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Identify kernel version and patch levelRun 'getprop ro.build.version.security_patch' on Android device to get the monthly security patch dateAffected if Security patch level is earlier than the fix for A-239630493 (the specific date varies by device/carrier)
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Check for the vulnerable fdt_next_tag functionIf kernel source is accessible, grep for the fdt_next_tag function in libfdt or drivers/of/fdt.c and verify bounds checking is present around tag length calculationAffected if The fdt_next_tag function lacks proper integer overflow checks before using tag length in memory operations
A user is affected if they are running an Android kernel with FDT support enabled and their security patch level predates the fix for A-239630493, which can be confirmed by checking the kernel source for proper bounds checking in fdt_next_tag.
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 Android kernel security patch for A-239630493, which implements proper bounds checking in fdt_next_tag to prevent integer overflow during device tree parsing. This is delivered through Android monthly security updates.
- Consultation6.0 h
- Implementation12.0 h
- Testing12.0 h
- Review / QA8.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $10,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-21065 — 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-2023-21065 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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