CVE-2021-38448

Arbitrary code execution via unsanitized code syntax

Published Nov 22, 2021 · Updated Aug 4, 2024

Code injection in Trane Symbio controller firmware allows physically proximate attackers to execute arbitrary code on affected controllers. The controller fails to sanitize input containing code syntax before using it in a way that can alter the intended controller flow. Physical access is required, and crafted code can compromise controller confidentiality, integrity, and availability.

CVSS severity7.5
High
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in Trane Symbio controller firmware allows physically proximate attackers to execute arbitrary code on affected controllers. The controller fails to sanitize input containing code syntax before using it in a way that can alter the intended controller flow. Physical access is required, and crafted code can compromise controller confidentiality, integrity, and availability.

The record

CVE
CVE-2021-38448
Published
Nov 22, 2021
Updated
Aug 4, 2024
Vendor
Trane
Product
Symbio
Classifications
CWE-94
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 22, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=700 <1.00.0023
  2. Affected versionversion=800 <1.00.0007

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Trane · Symbioversion=700 <1.00.0023; version=800 <1.00.0007

Published CVSS scores

4.6NIST NVDAV:L/AC:L/Au:N/C:P/I:P/A:P
7.6NIST NVDCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
7.5ICS-CERTCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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