CVE-2018-21086
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 · uneditedAn issue was discovered on Samsung mobile devices with L(5.x), M(6.0), and N(7.x) software. There is a race condition with a resultant double free in vnswap_init_backing_storage. The Samsung ID is SVE-2017-11177 (February 2018).
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 race condition vulnerability exists in Samsung's vnswap (virtual swap) kernel implementation on devices running Android L (5.x), M (6.0), and N (7.x). The race condition leads to a double-free memory corruption in the vnswap_init_backing_storage function, which could allow local privilege escalation or 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= 5.0= 5.0.1= 5.0.2= 5.1= 5.1.0= 5.1.1= 6.0= 7.0= 7.1.0= 7.1.1= 7.1.2CVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/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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Check Android versionGo to Settings > About Phone > Android version or run 'getprop ro.build.version.release' via ADB shellAffected if Version matches 5.0, 5.0.1, 5.0.2, 5.1, 5.1.0, 5.1.1, 6.0, 7.0, 7.1.0, 7.1.1, or 7.1.2
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Verify device manufacturerCheck Settings > About Phone > Manufacturer or run 'getprop ro.product.manufacturer' via ADB shellAffected if Device is manufactured by Samsung (vnswap is Samsung-specific)
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Check if vnswap kernel module is presentRun 'ls /sys/block/*/queue/rotational' to identify swap devices, or check /proc/swaps for active swap, or search for vnswap in /proc/modules via ADB shellAffected if vnswap module is loaded or vnswap swap device exists in /proc/swaps
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Confirm vnswap is enabled and in useCheck /proc/swaps output or run 'swapon --all' with verbose output to see swap devices in useAffected if A swap device named 'vnswap' or 'swapvnswap' appears in the active swap list
If the device is a Samsung running any Android version from 5.0 through 7.1.2 with vnswap enabled as an active swap device, the environment is affected by this vulnerability.
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 Samsung security updates released after February 2018 to patch the race condition and double-free vulnerability in vnswap. Devices should be updated to newer Android versions (Oreo 8.x or later) that contain the fix.
- Consultation2.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-21086 — 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-2018-21086 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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