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Improper Certificate ValidationWeakness · CWE-295

CVE-2026-41859

HIGH · 7.8 CVSS v3.1 Published 2026-06-04
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
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
A network man-in-the-middle between nats-sync and the BOSH director can steal the director credentials (Basic auth header or UAA client secret) and can tamper with the VM list that is written into the NATS authorization file. Stolen credentials grant administrative director access. UsersSync#bosh_api_response_body builds a Net::HTTP client with verify_mode = OpenSSL::SSL::VERIFY_NONE for every director call (/info, /deployments, /deployments/<name>/vms). Affected versions: - BOSH: all versions prior to v282.1.9 (inclusive); fixed in v282.1.9 or later

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

BOSH nats-sync component uses Net::HTTP with SSL verification disabled (VERIFY_NONE) when calling the director API endpoints (/info, /deployments, /deployments/<name>/vms). This allows a network MITM attacker to intercept Basic auth headers or UAA client secrets and tamper with VM authorization data.

MitigationUpgrade BOSH to v282.1.9 or later which restores proper SSL certificate verification, or ensure network isolation between nats-sync and the BOSH director to prevent MITM attacks.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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 the BOSH deployment version
    Run 'bosh env' or check your BOSH director version through the deployment manifests or the BOSH CLI
    Affected if The BOSH version is earlier than v282.1.9
  2. Locate the nats-sync component
    Search your BOSH deployment for the nats-sync job or package in your manifest; it is typically deployed as part of the BOSH infrastructure
    Affected if nats-sync is deployed as part of your BOSH installation
  3. Inspect the nats-sync source code for SSL verification
    Locate the nats-sync gem or source code and search for 'verify_mode' or 'VERIFY_NONE' within the UsersSync class
    Affected if The code shows verify_mode set to OpenSSL::SSL::VERIFY_NONE in the bosh_api_response_body method
  4. Check for SSL verification configuration in nats-sync
    Review the nats-sync configuration files or environment variables for any SSL verification settings; examine how the component initializes its HTTP client connection to the BOSH director
    Affected if SSL verification is explicitly disabled or not enforced when connecting to the BOSH director API

Your environment is affected if you are running BOSH versions before v282.1.9 with nats-sync deployed and the SSL verification is disabled in the nats-sync code or configuration.

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 BOSH to v282.1.9 or later which restores proper SSL certificate verification, or ensure network isolation between nats-sync and the BOSH director to prevent MITM attacks.

Recommended fix High confidence

BOSH v282.1.9 or later

  1. Identify the BOSH director deployment in your infrastructure
  2. Ensure you have a backup of current BOSH state before upgrading
  3. Upgrade the BOSH director to version v282.1.9 or later using your deployment mechanism
  4. After upgrade, verify that nats-sync now validates SSL certificates (verify_mode should be OpenSSL::SSL::VERIFY_PEER instead of VERIFY_NONE)
  5. Confirm that nats-sync can successfully communicate with the BOSH director over HTTPS with proper certificate validation
  6. Test that the /info, /deployments, and /deployments/<name>/vms API calls work correctly with SSL verification enabled
Caveat Ensure your BOSH director's TLS certificate is valid and properly signed; otherwise nats-sync connections will fail after enabling certificate validation

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

Have this fixed Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
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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-2026-41859 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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