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SaltApplication · Saltstack

CVE-2016-9639

CRITICAL · 9.1 CVSS v3.0 Published 2017-02-07
Fix available
A fix is available. Upgrade to after 2015.8.10 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 · unedited
Salt before 2015.8.11 allows deleted minions to read or write to minions with the same id, related to caching.

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 confidence

Salt before 2016.8.11 contains a cache invalidation flaw where deleted minions retain read/write access to resources associated with their minion ID. When a new minion registers with the same ID as a previously deleted minion, the cached authentication credentials from the deleted minion can be improperly reused, allowing unintended cross-minion data access.

MitigationUpgrade Salt to version 2015.8.11 or later. Additionally, rekey or re-register all minions to ensure new cryptographic credentials are generated and cached credentials from deleted minions are purged.

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
SaltApplication
Affected:<= 2015.8.10

CVSS 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
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the installed Salt version
    Run 'salt-master --version' or 'salt --version' on the Salt master host. Also check package manager output: 'rpm -q salt-master' or 'dpkg -l salt-master'.
    Affected if The version is 2015.8.10 or earlier (any version <= 2015.8.10).
  2. Verify the Salt master service is running
    Check process status: 'ps aux | grep salt-master' or 'systemctl status salt-master' or 'service salt-master status'.
    Affected if The Salt master is actively running and accepting minion connections.
  3. Review minion key management history
    Run 'salt-key -L' to list all accepted, unaccepted, and rejected minion keys. Look for patterns where minions may have been removed and re-added with the same minion ID.
    Affected if There are minions with IDs that were previously deleted and then re-registered with the same ID.
  4. Inspect the minion credential cache
    Examine the Salt master's PKI directory (typically /etc/salt/pki/master/minions/) for cached authentication data. Compare timestamps on key files to identify recently added keys with previously existing IDs.
    Affected if The master contains cached credentials that may persist from previously deleted minions with matching IDs.

You are affected if your Salt version is 2015.8.10 or earlier, the master service is running, and minions have been deleted and re-registered with the same minion IDs, causing cached credentials to be reused.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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.

dbcve · scoped
Upgrade available Upgrade to a release after 2015.8.10
Interim mitigation

Upgrade Salt to version 2015.8.11 or later. Additionally, rekey or re-register all minions to ensure new cryptographic credentials are generated and cached credentials from deleted minions are purged.

Recommended fix High confidence

Salt 2015.8.11 or later (recommended: latest stable 2015.8.x or migrate to a newer major release)

  1. Check current Salt version using 'salt --version' or 'salt-master --version'
  2. Back up Salt configuration directory (typically /etc/salt) and any custom state files
  3. Upgrade Salt to version 2015.8.11 or later using your package manager (e.g., 'yum update salt' or 'apt-get install salt')
  4. After upgrade, restart the salt-master service: 'systemctl restart salt-master'
  5. As a security precaution, clear any cached minion data for deleted minions by removing files in /var/cache/salt/master/minions/ for affected minion IDs
  6. Verify the new version is running: 'salt --version'
Caveat Review custom Salt states and modules for compatibility with newer version; test thoroughly in non-production environment first

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Salt Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2016-9639 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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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