CVE-2021-27660
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 · uneditedAn insecure client auto update feature in C-CURE 9000 can allow remote execution of lower privileged Windows programs.
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 confidenceC-CURE 9000 has an insecure client auto-update feature that fails to properly validate updates before execution. This allows an attacker to supply malicious code that gets executed on client systems with the privileges of the auto-update client, enabling remote code execution without requiring administrative credentials.
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< 2.80CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify C-CURE 9000 installationCheck for C-CURE 9000 client or server software on the system. Look for installation directories (commonly under C:\Program Files\C-CURE or similar), or check Windows Programs and Features for 'C-CURE 9000' entries.Affected if The C-CURE 9000 software is present on the system.
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Determine firmware versionLocate the firmware version information. For the C-CURE 9000 server, check the About or System Information section in the C-CURE 9000 management interface. Alternatively, check the software version via the Windows Programs and Features list or the executable version properties.Affected if The firmware version is lower than 2.80.
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Verify auto-update client is enabledCheck the C-CURE 9000 client configuration for auto-update settings. This is typically found in the client configuration files (often with .config or .xml extensions in the C-CURE installation directory) or within the client settings in the management interface.Affected if The client auto-update feature is enabled and configured.
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Inspect update transfer mechanismReview the client configuration files or settings to determine if update downloads use HTTP (insecure) or HTTPS (secure). Check the update server URL configuration in the client settings or configuration files.Affected if Updates are configured to transfer over HTTP instead of HTTPS, or certificate validation is disabled.
A system is affected if C-CURE 9000 firmware version is below 2.80 AND the client auto-update feature is enabled with insecure update transfer (HTTP) or disabled certificate validation.
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.
dbcve · scoped2.80
Implement cryptographically secure code signing for all client updates with proper certificate validation, enforce HTTPS for all update transfers, and add integrity verification (hash/checksum validation) before executing any downloaded updates.
C-CURE 9000 Firmware version 2.80 or later
- Verify current C-CURE 9000 firmware version by accessing the system admin interface or release notes
- Download C-CURE 9000 firmware version 2.80 or later from the official Johnson Controls/C-CURE portal
- Follow the standard firmware upgrade procedure documented in the C-CURE 9000 installation guide
- Ensure the upgrade is performed during a planned maintenance window with proper backups of configuration data
- After upgrade, verify the client auto update feature is functioning correctly and that the vulnerability is remediated
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation8.0 h
- Implementation24.0 h
- Testing12.0 h
- Review / QA6.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-27660 — 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-2021-27660 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
- No weaponised exploit code, or anything meant to cause harm
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