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Couchbase ServerApplication · Couchbase

CVE-2019-11495

CRITICAL · 9.8 CVSS v3.1 Published 2019-09-10
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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
In Couchbase Server 5.1.1, the cookie used for intra-node communication was not generated securely. Couchbase Server uses erlang:now() to seed the PRNG which results in a small search space for potential random seeds that could then be used to brute force the cookie and execute code against a remote system. This has been fixed in version 6.0.0.

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 confidence

Couchbase Server 5.1.1 uses erlang:now() to seed its pseudo-random number generator for creating intra-node communication cookies. This function returns a limited set of values based on system time, creating a small seed space that can be brute-forced. An unauthenticated remote attacker can derive the cookie and execute arbitrary code on the affected system.

MitigationUpgrade Couchbase Server to version 6.0.0 or later, which uses a cryptographically secure random number generator for cookie generation. Prior to upgrade, restrict inter-node communication to trusted networks to reduce attack surface.

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
Couchbase ServerApplication
Affected:= 5.1.1

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
High

CVSS:3.1/AV:N/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 checks

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

  1. Identify Couchbase Server version
    Run 'cbversion' from the Couchbase bin directory, or check the product version via the admin web UI under Server Nodes > version, or inspect the installation manifest
    Affected if The installed version is exactly 5.1.1 (no other versions are affected by this CVE)
  2. Verify inter-node communication ports are exposed
    Check network configuration for open ports used by Couchbase inter-node communication (typically 8091, 8092, 11210, 21100-21199). Use 'netstat -an' or 'ss -tlnp' to list listening ports, or review firewall rules
    Affected if Inter-node communication ports are reachable from untrusted networks (the attacker needs network access to brute-force the cookie)
  3. Confirm Erlang cookie generation is in use
    Review Couchbase logs for Erlang-related startup messages, or verify the node is participating in a cluster (clustered nodes use cookies for intra-node communication)
    Affected if The Couchbase node is part of a cluster and using Erlang-based inter-node communication (the vulnerability only applies to clustered deployments)

A system is affected only if it runs Couchbase Server version 5.1.1 AND has inter-node communication ports exposed to untrusted networks, as the attacker needs network access to brute-force the cookie seeded by erlang:now().

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Couchbase Server to version 6.0.0 or later, which uses a cryptographically secure random number generator for cookie generation. Prior to upgrade, restrict inter-node communication to trusted networks to reduce attack surface.

Recommended fix High confidence

Couchbase Server 6.0.0

  1. 1. Create a complete backup of all Couchbase buckets, views, and cluster configuration
  2. 2. Review Couchbase Server 6.0.0 release notes for any configuration or feature changes that may affect your deployment
  3. 3. Ensure your infrastructure meets the minimum requirements for version 6.0.0 (check OS compatibility, memory, disk space)
  4. 4. Stop all applications connecting to the Couchbase cluster
  5. 5. For single-node deployments: stop the Couchbase service, install version 6.0.0, and start the service
  6. 6. For multi-node clusters: follow Couchbase rolling upgrade procedure, upgrading one node at a time while maintaining cluster quorum
  7. 7. After upgrade, verify the cluster is healthy using `cbcluster stats` or the admin console
  8. 8. Confirm the intra-node communication cookie is now generated using a secure PRNG (the vulnerability is remediated in this version)
Caveat Major version upgrade from 5.1.1 to 6.0.0 may include feature deprecations, API changes, and requires thorough testing in a non-production environment before production deployment

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

Fix this in Couchbase Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,380
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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-2019-11495 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
  • No spam, self-promotion, credentials, or personal data