CVE-1999-0166
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 · uneditedNFS allows users to use a "cd .." command to access other directories besides the exported file system.
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 · moderate confidenceThis is a historical NFS (Network File System) vulnerability from 1999 where improper export configuration allows users to escape the intended share boundary using 'cd ..' to traverse to parent directories outside the exported filesystem. This represents a path traversal vulnerability in NFS export definitions.
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
- Network
- Complexity
- Low
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- None
- Availability
- None
AV:N/AC:L/Au:N/C:P/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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Identify if NFS is runningUse 'showmount -e localhost' or check for nfsd processes with 'ps aux | grep nfs'Affected if NFS daemon is active and exporting paths
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Review NFS export configurationExamine /etc/exports (or /etc/exports.d/*) file contents to list all exported pathsAffected if Any export entries exist that grant filesystem access
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Identify overly broad export pathsCompare exported paths to actual mount points - check if parent directories (like '/' or '/home') are exported when only subdirectories should be sharedAffected if Export entries use parent directory paths rather than specific leaf directories
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Check for missing subtree restrictionsLook for export options - verify if 'no_subtree_check' appears without corresponding explicit path restrictionsAffected if Exports use no_subtree_check without limiting to specific subdirectories
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Verify export access controlsReview each export entry for client access restrictions (IP/hostname limits) and root_squash mappingAffected if Exports allow unrestricted access from any client or lack root_squash
The environment is affected if NFS exports contain overly broad path definitions that allow traversal beyond the intended share boundary to parent directories.
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 dataConfigure NFS exports with explicit, minimal path restrictions using the 'no_subtree_check' option combined with 'root_squash' and ensure exports are limited to specific directories rather than parent mount points.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 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 $2,800.
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Free · runs locallyCheck whether your project pulls in CVE-1999-0166 — 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-1999-0166 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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