Linux KernelOperating system · Linux
CVE-2018-1118
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 · uneditedLinux kernel vhost since version 4.8 does not properly initialize memory in messages passed between virtual guests and the host operating system in the vhost/vhost.c:vhost_new_msg() function. This can allow local privileged users to read some kernel memory contents when reading from the /dev/vhost-net device file.
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 confidenceThe vhost-net driver in Linux kernel versions since 4.8 fails to properly initialize memory in the vhost_new_msg() function when handling messages between virtual guests and the host OS. This uninitialized memory can be leaked to local privileged users through reads from the /dev/vhost-net device file, allowing disclosure of arbitrary kernel memory contents.
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
Linux KernelOperating system
>= 4.8, < 4.18
Debian LinuxOperating system
= 8.0
Ubuntu LinuxOperating system
= 16.04= 18.04
Virtualization HostApplication
= 4.0
Enterprise Linux DesktopOperating system
= 7.0
Enterprise Linux ServerOperating system
= 7.0
Enterprise Linux WorkstationOperating system
= 7.0CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
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 kernel versionRun 'uname -r' to get the running kernel version. Compare it against the affected range: >= 4.8 and < 4.18. Versions 4.18 and later contain the fix.Affected if The kernel version is 4.8.x through 4.17.x inclusive.
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Verify vhost-net device existsCheck if /dev/vhost-net exists by running 'ls -la /dev/vhost-net' or 'test -c /dev/vhost-net && echo exists'.Affected if The /dev/vhost-net device file is present on the system.
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Check for active vhost-net usageRun 'lsmod | grep vhost' to see if the vhost_net kernel module is loaded, or check for QEMU/KVM processes using vhost-net with 'ps aux | grep -i qemu' or 'lsof /dev/vhost-net'.Affected if The vhost_net module is loaded or processes are actively using /dev/vhost-net.
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Assess access permissions to /dev/vhost-netRun 'ls -la /dev/vhost-net' to view group and world read/write permissions. Also check which users or groups have access via 'getent group | grep -i vhost' if applicable.Affected if Non-root users or untrusted local users have read or write access to /dev/vhost-net.
The system is affected if it runs a kernel between version 4.8 and 4.17 inclusive, has the /dev/vhost-net device available, and permits untrusted local users to access that device.
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 data4.18
Update the Linux kernel to a version that includes the fix for proper memory initialization in vhost_new_msg(). Alternatively, restrict access to /dev/vhost-net to minimize exposure to untrusted local users.
Fix this in Linux Kernel
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-1118 — 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-2018-1118 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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