CVE-2026-28252Public exploitNetwork attack vector

Pre-auth root shell via deterministic response cipher

Published Mar 12, 2026 · Updated Mar 12, 2026

Authentication bypass in Trane Tracer SC, Tracer SC+, and Tracer Concierge allows remote attackers to obtain a root SSH shell. The custom PAM provider's pam_sm_authenticate path derives each expected challenge response with a deterministic modified substitution cipher that uses no secret. The diagnostic SSH service is disabled by default and must be manually enabled; successful access permits arbitrary commands with root privileges.

CVSS severity9.2
Critical
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Trane Tracer SC, Tracer SC+, and Tracer Concierge allows remote attackers to obtain a root SSH shell. The custom PAM provider's pam_sm_authenticate path derives each expected challenge response with a deterministic modified substitution cipher that uses no secret. The diagnostic SSH service is disabled by default and must be manually enabled; successful access permits arbitrary commands with root privileges.

The record

CVE
CVE-2026-28252
Published
Mar 12, 2026
Updated
Mar 12, 2026
Vendor
Trane
Product
Tracer SC
Classifications
CWE-327, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 12, 2026Record 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=0 <v4.4 SP7
  2. Affected versionversion=0 <v6.3.2310

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Trane · Tracer SCversion=0 <v4.4 SP7; version=0 <v6.3.2310
Trane · Tracer Conciergeversion=0 <v6.3.2310

Published CVSS scores

9.2ICS-CERTCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-327Use of a Broken or Risky Cryptographic Algorithm
T1190Exploit Public-Facing Application

Public exploit references

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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