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GatewayApplication · Codesys

CVE-2022-31803

MEDIUM · 5.3 CVSS v3.1 Published 2022-06-24
Fix available
A fix is available. Upgrade to 2.3.9.38 or later.
See remediation →
62/100
Remediation priority · Elevated
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
In CODESYS Gateway Server V2 an insufficient check for the activity of TCP client connections allows an unauthenticated attacker to consume all available TCP connections and prevent legitimate users or clients from establishing a new connection to the CODESYS Gateway Server V2. Existing connections are not affected and therefore remain intact.

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 confidence

In CODESYS Gateway Server V2, the server lacks proper validation of TCP client connection activity, allowing an unauthenticated attacker to open numerous TCP connections without proper tracking or limits. This exhausts the available connection pool, preventing legitimate clients from connecting while existing established connections remain unaffected.

MitigationApply vendor patches when available; until then, consider network-level protections such as rate limiting, firewall rules restricting source IPs, or connection limits at the network edge to mitigate unauthenticated connection flooding.

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
GatewayApplication
Affected:>= 2.0, < 2.3.9.38

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
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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. Identify CODESYS Gateway V2 installation and version
    Locate the CODESYS Gateway installation directory and check the executable or product version information. Common locations include C:\Program Files\CODESYS or /opt/codesys. Check the Gateway's about dialog, log files, or version metadata.
    Affected if Installed version is 2.0 or higher but lower than 2.3.9.38
  2. Verify Gateway TCP listener is active
    Check if the CODESYS Gateway service is running and listening on expected TCP ports (typically 1217, 1218, or 2455). Use netstat or similar tool: netstat -an | grep -E '1217|1218|2455' or Get-NetTCPConnection on Windows.
    Affected if The Gateway is running and accepting TCP connections on any port, making it network-accessible
  3. Monitor current TCP connection count
    Review the number of active TCP connections to the Gateway port(s). Use netstat to count connections: netstat -an | grep <port> | grep ESTABLISHED | wc -l
    Affected if A high number of concurrent connections is observed, especially from few or single source IPs, potentially exhausting the connection pool
  4. Check for connection pool exhaustion symptoms
    Observe if legitimate clients report connection refused or timeout errors when attempting to connect to the Gateway. Review Gateway logs for connection-related errors or warnings.
    Affected if Legitimate clients cannot establish new connections while existing connections work, or logs show connection pool exhaustion warnings

The environment is affected if CODESYS Gateway V2 version 2.0 through 2.3.9.38 is running and network-accessible, with observable connection exhaustion or high connection counts from unauthenticated sources.

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 2.3.9.38 or later
Fixed in 2.3.9.38
Interim mitigation

Apply vendor patches when available; until then, consider network-level protections such as rate limiting, firewall rules restricting source IPs, or connection limits at the network edge to mitigate unauthenticated connection flooding.

Recommended fix Moderate confidence

2.3.9.38 or later

  1. 1. Identify all CODESYS Gateway Server V2 instances currently deployed in your environment.
  2. 2. Check the current version of each Gateway instance using the product's version information or system information.
  3. 3. For any Gateway with version >= 2.0 and < 2.3.9.38, plan for an upgrade to version 2.3.9.38 or later.
  4. 4. Before upgrading, review release notes and ensure compatibility with your existing CODESYS development environment and runtime components.
  5. 5. Perform the upgrade following the vendor's standard upgrade procedure for CODESYS Gateway Server V2.
  6. 6. After upgrading, verify that the Gateway accepts new TCP client connections properly and that resource consumption is within normal limits.

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

Fix this in Gateway Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,640
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,624.

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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-2022-31803 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