CVE-1999-0084
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 · uneditedCertain NFS servers allow users to use mknod to gain privileges by creating a writable kmem device and setting the UID to 0.
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 confidenceCertain NFS servers allow local users to exploit the mknod command to create a writable kmem device file and set the UID to 0, granting privileged (root) access to kernel memory and enabling complete system compromise through privilege escalation.
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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/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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Determine if an NFS server is runningRun 'ps -ef | grep nfsd' or 'rpcinfo -p' to list RPC services and look for nfsd entriesAffected if An NFS server daemon (nfsd) is running and serving files
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Locate the exports configuration fileCheck /etc/exports (or /etc/dfs/dfstab on some Sun systems) for NFS share definitionsAffected if The exports file contains entries without root_squash or all_squash options, allowing UID mapping to root (0)
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Inspect for writable kmem device filesRun 'ls -la /dev/kmem' and check permissions - also search for any recently created kmem files: 'find / -name kmem -type c 2>/dev/null'Affected if A writable (mode 666 or similar) kmem device file exists outside of /dev, or a kmem file with UID 0 (root) ownership is found in a non-standard location
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Check for suspicious device files created via mknodReview system for character device files in unusual locations: 'find / -type c -perm -002 2>/dev/null' looking for kmem, mem, or null devices outside /devAffected if Any writable kernel memory device files (kmem, mem) exist with permissive permissions or appear in unexpected directories indicating exploitation
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Verify NFS daemon version if identifiableCheck the NFS server version via 'rpcinfo -s' or review the NFS server binary if accessible: 'file /usr/lib/nfs/nfsd' or similar pathAffected if The NFS server is Sun's implementation and cannot be confirmed as patched (older Sun NFS versions are affected)
A system is affected if it runs a Sun NFS server (any version) with exports allowing UID mapping to root and contains a writable kmem device file indicating successful exploitation of 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 vendor patches to the affected NFS server implementation, enable root_squash in exports to prevent UID mapping to root, and restrict NFS access to trusted networks only.
- 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-1999-0084 — 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-1999-0084 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
- No weaponised exploit code, or anything meant to cause harm
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