CVE-2021-27459
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 · uneditedA vulnerability has been found in multiple revisions of Emerson Rosemount X-STREAM Gas Analyzer. The webserver of the affected products allows unvalidated files to be uploaded, which an attacker could utilize to execute arbitrary code.
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 · high confidenceThe Emerson Rosemount X-STREAM Gas Analyzer webserver contains an unauthenticated file upload vulnerability. The web interface does not validate uploaded files, allowing an attacker to upload malicious files and achieve arbitrary code execution on the device.
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 dataall versionsall versionsall versionsall versionsCVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/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 the device model and firmware versionAccess the device web interface or check the system information page. Look for model numbers Xegp, Xegk, Xefd, or Xexf in the device documentation or web interface. Check the firmware version information typically found under Settings, About, or System Info in the web interface.Affected if The device is an Emerson X-STREAM Enhanced model (Xegp, Xegk, Xefd, or Xexf) with any firmware version.
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Verify the webserver is accessibleAttempt to access the device web interface via HTTP/HTTPS using the device IP address. Confirm the web interface loads and displays the login or status page.Affected if The web interface is reachable on the network.
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Check if file upload functionality exists without authenticationNavigate through the web interface without logging in. Look for file upload, configuration upload, firmware upload, or similar features in the public sections. Check for endpoints that accept file uploads without requiring authentication.Affected if The web interface exposes a file upload feature that is accessible without authentication.
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Inspect upload endpoint behaviorIf a file upload feature is found, attempt to send a test request to the upload endpoint. Observe if the server accepts files without validating content type, extension, or requiring user authentication.Affected if The server accepts file uploads without authentication or validation.
You are affected if you have an Emerson X-STREAM Enhanced gas analyzer (Xegp, Xegk, Xefd, or Xexf) with an accessible web interface that allows unauthenticated file uploads.
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.
From vendor dataImplement strict file upload validation (file type, extension, content inspection) on the webserver, restrict upload functionality to authenticated users only, apply vendor patches when available, and place the device behind a network firewall to limit exposure.
- Consultation8.0 h
- Implementation12.0 h
- Testing10.0 h
- Review / QA6.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-27459 — 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-2021-27459 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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