PostgreSQLDatabase / datastore
CVE-2017-8806
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 · uneditedThe Debian pg_ctlcluster, pg_createcluster, and pg_upgradecluster scripts, as distributed in the Debian postgresql-common package before 181+deb9u1 for PostgreSQL (and other packages related to Debian and Ubuntu), handled symbolic links insecurely, which could result in local denial of service by overwriting arbitrary files.
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 confidenceThe Debian postgresql-common scripts (pg_ctlcluster, pg_createcluster, pg_upgradecluster) handled symbolic links insecurely when managing PostgreSQL cluster directories and files. This allowed a local attacker with write access to certain directories to create malicious symlinks that the scripts would follow, potentially overwriting arbitrary system files and causing local 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
PostgreSQLDatabase / datastore
all 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/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 postgresql-common package versionRun: dpkg -l postgresql-common (Debian/Ubuntu) or rpm -qa | grep postgresql-common (RHEL-based)Affected if Version is lower than 181+deb9u1 on Debian 9, or lower than equivalent patched version on other distributions
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Locate vulnerable management scriptsRun: which pg_ctlcluster pg_createcluster pg_upgradeclusterAffected if Scripts exist from an unpatched postgresql-common package
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Check PostgreSQL data directory permissionsRun: ls -la $(pg_config --data-dir) or ls -la /var/lib/postgresql/ (examine the parent directory)Affected if Directory is world-writable (permissions like 777) or group-writable with untrusted users in the group
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Identify user access to PostgreSQL directoriesRun: getent group pg or check /var/lib/postgresql ownership and group membershipAffected if Untrusted or non-admin users have write access to PostgreSQL data directories
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Audit for suspicious symlinks in PostgreSQL pathsRun: find /var/lib/postgresql -type l -ls and find /etc/postgresql -type l -lsAffected if Any symlinks exist in these directories pointing to unexpected locations outside the PostgreSQL hierarchy
A system is affected if it runs an unpatched postgresql-common version below 181+deb9u1 AND has directories or configuration locations that are writable by untrusted local users who could plant malicious symlinks.
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 dataUpdate postgresql-common to version 181+deb9u1 or later for Debian 9, or apply equivalent vendor patches. For older systems, ensure only trusted users have write access to PostgreSQL data directories and avoid running cluster management scripts in world-writable locations.
Fix this in PostgreSQL
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-8806 — 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-2017-8806 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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- Version or environment caveats, and links to real fixes
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