CVE-2021-27459Network attack vector

Unauthenticated code execution via unvalidated file upload

Published May 20, 2021 · Updated Aug 3, 2024

Unrestricted file upload in Emerson Rosemount X-STREAM Gas Analyzer all revisions allows remote attackers to execute arbitrary code. The embedded webserver accepts an uploaded file without validating its type and permits the uploaded content to be used for code execution; public records disclose no endpoint details. Unauthenticated network reachability is sufficient, and successful exploitation runs attacker-supplied code on the analyzer.

CVSS severity9.8
Critical
EPSS probability1.75%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unrestricted file upload in Emerson Rosemount X-STREAM Gas Analyzer all revisions allows remote attackers to execute arbitrary code. The embedded webserver accepts an uploaded file without validating its type and permits the uploaded content to be used for code execution; public records disclose no endpoint details. Unauthenticated network reachability is sufficient, and successful exploitation runs attacker-supplied code on the analyzer.

The record

CVE
CVE-2021-27459
Published
May 20, 2021
Updated
Aug 3, 2024
Vendor
Emerson Electric Co.
Product
Rosemount X-STREAM Gas Analyzer
Classifications
CWE-434, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 20, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=X-STREAM enhanced XEGP – all revisions, X-STREAM enhanced XEGK – all revisions, X-STREAM enhanced XEFD – all revisions, X-STREAM enhanced XEXF – all revisions

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Emerson Electric Co. · Rosemount X-STREAM Gas Analyzerversion=X-STREAM enhanced XEGP – all revisions, X-STREAM enhanced XEGK – all revisions, X-STREAM enhanced XEFD – all revisions, X-STREAM enhanced XEXF – all revisions

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS: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 exploitUnconfirmed

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1190Exploit Public-Facing Application

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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