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Codesys Runtime SystemApplication · 3s Software

CVE-2018-5440

CRITICAL · 9.8 CVSS v3.1 Published 2018-02-15
Fix available
A fix is available. Upgrade to 1.1.9.19 or later.
See remediation →
100/100
Remediation priority · Urgent
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 Stack-based Buffer Overflow issue was discovered in 3S-Smart CODESYS Web Server. Specifically: all Microsoft Windows (also WinCE) based CODESYS web servers running stand-alone Version 2.3, or as part of the CODESYS runtime system running prior to Version V1.1.9.19. A crafted request may cause a buffer overflow and could therefore execute arbitrary code on the web server or lead to a denial-of-service condition due to a crash in the web server.

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

A stack-based buffer overflow vulnerability exists in the 3S-Smart CODESYS Web Server component. Attackers can send a specially crafted HTTP request to trigger the overflow, potentially executing arbitrary code on the affected system or causing a denial-of-service via crash. The vulnerability affects Windows and WinCE-based CODESYS web servers running standalone Version 2.3 or as part of the runtime system prior to Version V1.1.9.19.

MitigationUpdate the CODESYS web server or runtime system to Version V1.1.9.19 or later. If immediate patching is not possible, restrict network access to the web server port and monitor for anomalous requests.

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
Codesys Runtime SystemApplication
Affected:< 1.1.9.19
Codesys Web ServerApplication
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
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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify if CODESYS Web Server component is present
    Inspect the system for installation of 3S-Smart CODESYS Web Server version 2.3 or check for CODESYS Runtime System components
    Affected if The CODESYS Web Server version 2.3 is installed, or the CODESYS Runtime System version is below 1.1.9.19
  2. Determine the installed Web Server version
    Check the installed CODESYS Web Server version - the affected version is specifically 2.3
    Affected if The installed version is exactly 2.3
  3. Determine the installed Runtime System version
    Check the installed CODESYS Runtime System version - the affected range is anything less than 1.1.9.19
    Affected if The installed Runtime System version is prior to 1.1.9.19
  4. Confirm the web server is exposed to network
    Verify the CODESYS web server port (typically HTTP port 80 or 8080) is listening and accessible from the network
    Affected if The web server component is actively running and network-accessible

The system is affected if CODESYS Web Server version 2.3 or CODESYS Runtime System version prior to 1.1.9.19 is installed and the web server component is enabled and accessible on Windows or WinCE platforms.

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 1.1.9.19 or later
Fixed in 1.1.9.19
Interim mitigation

Update the CODESYS web server or runtime system to Version V1.1.9.19 or later. If immediate patching is not possible, restrict network access to the web server port and monitor for anomalous requests.

Recommended fix Moderate confidence

CODESYS Runtime System: V1.1.9.19 or later; CODESYS Web Server: version beyond 2.3 (contact vendor for exact patched release)

  1. Identify the currently installed CODESYS product (Web Server version 2.3 or Runtime System version < V1.1.9.19)
  2. For CODESYS Runtime System: Upgrade to version V1.1.9.19 or later
  3. For standalone CODESYS Web Server: Upgrade from version 2.3 to a later patched version (contact 3S-Smart for specific patched version)
  4. After upgrading, verify the web server is functioning correctly
  5. Test that the previously vulnerable endpoint no longer crashes or allows overflow
Caveat Review 3S-Smart release notes for version V1.1.9.19 to check for any breaking changes or API changes that may affect existing applications

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

Fix this in Codesys Runtime System Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,840
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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-2018-5440 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