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OpenerApplication · Opener Project

CVE-2021-27498

HIGH · 7.5 CVSS v3.1 Published 2022-05-12
Fix available
A fix is available. Upgrade to after 2.3 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable 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
A specifically crafted packet sent by an attacker to EIPStackGroup OpENer EtherNet/IP commits and versions prior to Feb 10, 2021 may result in a denial-of-service condition.

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

A denial-of-service vulnerability exists in EIPStackGroup OpENer EtherNet/IP server implementations where specially crafted EtherNet/IP packets can cause the service to become unresponsive or crash, likely due to improper input handling or parsing logic in the packet processing code.

MitigationUpdate OpENer EtherNet/IP library to the version released after February 10, 2021 which contains the vendor fix, or apply the specific patch addressing the malformed packet handling vulnerability.

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
OpenerApplication
Affected:<= 2.3

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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. Locate OpENer installation
    Search for files named 'Opener', 'EIPStackGroup', or 'OpENer' in your system, or check running processes for 'Opener' or 'EtherNet/IP' related services
    Affected if OpENer software is present on the system
  2. Identify OpENer version
    Check version information in the OpENer binary, library files, or associated manifest/config files - compare against the affected version 2.3 and earlier
    Affected if The installed version is 2.3 or any earlier version
  3. Verify EtherNet/IP server is enabled
    Check OpENer configuration files or startup scripts for EtherNet/IP server daemon being activated, typically through command-line arguments or config flags enabling the network listener
    Affected if The EtherNet/IP server component is enabled and listening on network ports
  4. Confirm network exposure
    Check if the EtherNet/IP service is bound to accessible network interfaces (ports 44818 for EtherNet/IP or 2222 for explicit messaging) and is reachable from network
    Affected if The service is exposed on accessible network ports

Your environment is affected if OpENer version 2.3 or earlier is deployed and the EtherNet/IP server component is enabled and network-accessible.

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 a release after 2.3
Interim mitigation

Update OpENer EtherNet/IP library to the version released after February 10, 2021 which contains the vendor fix, or apply the specific patch addressing the malformed packet handling vulnerability.

Recommended fix High confidence

OpENer version 2.4 or later, or commit hash after Feb 10, 2021

  1. 1. Identify the current OpENer version in use by checking project metadata or build configuration
  2. 2. Download the latest stable release of OpENer from the official GitHub repository (github.com/EIPStackGroup/OpENer)
  3. 3. Review the release notes to confirm the fix for CVE-2021-27498 is included (versions released after February 2021)
  4. 4. Replace the vulnerable OpENer binaries or source code with the updated version
  5. 5. Rebuild and redeploy the application using the patched OpENer library
  6. 6. Test the EtherNet/IP implementation to verify normal functionality
Caveat Review release notes for any API changes between 2.3 and the target version; minor version upgrades typically maintain backward compatibility

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

Fix this in Opener Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.

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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-2021-27498 in production — separate from our analysis above.

No notes yet

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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