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Symbio 700Application · Trane

CVE-2021-38448

HIGH · 7.6 CVSS v3.1 Published 2021-11-22
Fix available
A fix is available. Upgrade to 1.00.0023 / 1.10.0010 or later.
See remediation →
81/100
Remediation priority · High
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
The affected controllers do not properly sanitize the input containing code syntax. As a result, an attacker could craft code to alter the intended controller flow of the software.

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

The affected controllers fail to properly sanitize input containing code syntax, allowing attackers to inject and execute arbitrary code that alters the intended controller flow. This is a code injection vulnerability in the controller layer where user-supplied input is not validated before being processed as code or used to determine program execution paths.

MitigationImplement proper input validation and sanitization on all controller endpoints, using allowlist validation where possible and ensuring all user input is treated as data rather than code.

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
Symbio 700Application
Affected:< 1.00.0023
Symbio 800Application
Affected:< 1.30.0008< 1.10.0010

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
Physical
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/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 Trane Symbio model
    Access the device web interface, administrative console, or SNMP interface and confirm the model number is Symbio 700 or Symbio 800
    Affected if Model is Trane Symbio 700 or Symbio 800
  2. Check Symbio 700 firmware version
    In the device web interface, navigate to System Info, About, or Settings section to view the firmware version. Compare against 1.00.0023
    Affected if Model is Symbio 700 and firmware version is below 1.00.0023
  3. Check Symbio 800 firmware version
    In the device web interface, navigate to System Info, About, or Settings section to view the firmware version. Compare against 1.30.0008 and 1.10.0010
    Affected if Model is Symbio 800 and firmware version is below 1.10.0010 OR between 1.10.0010 and 1.30.0008 (inclusive of 1.10.0010 to 1.30.0007)
  4. Verify network accessibility
    Confirm the device has an active network connection and web/API interfaces are accessible from network segments where attackers could send malicious input
    Affected if Device network interfaces are exposed to untrusted networks

You are affected if you have a Trane Symbio 700 below version 1.00.0023 or a Symbio 800 below version 1.10.0010 (or between 1.10.0010 and 1.30.0008) with accessible network interfaces.

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 1.00.0023 / 1.10.0010 / 1.30.0008 or later
Fixed in 1.00.00231.10.00101.30.0008
Interim mitigation

Implement proper input validation and sanitization on all controller endpoints, using allowlist validation where possible and ensuring all user input is treated as data rather than code.

Recommended fix Moderate confidence

Symbio 700: 1.00.0023 or later; Symbio 800: 1.30.0008 or later (or 1.10.0010 depending on subseries)

  1. 1. Identify the specific Symbio model in use (700 or 800 series)
  2. 2. Determine the current installed version of the Symbio software
  3. 3. For Symbio 700: Upgrade to version 1.00.0023 or later
  4. 4. For Symbio 800: Upgrade to version 1.30.0008 or later (or 1.10.0010 depending on the subseries)
  5. 5. Obtain the firmware/software update from the vendor's official distribution channel
  6. 6. Follow the vendor's documented upgrade procedure, ensuring the upgrade is performed in a controlled manner
  7. 7. After upgrade, verify the version has been correctly applied
  8. 8. Test that the code injection vulnerability is no longer exploitable
Caveat Review vendor release notes for any compatibility considerations or configuration changes required after upgrade

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

Fix this in Symbio 700 Scoped from the published advisory
  • Consultation4.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,600
Get the upgrade done

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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-2021-38448 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