VisualizationApplication · Codesys

CVE-2026-0393

MEDIUM · 6.5 CVSS v3.1 Published 2026-05-21
Fix available
A fix is available. Upgrade to 4.10.0.0 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable 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
The affected product may expose credentials remotely between low privileged visualization users during concurrent login operations due to insufficient isolation of authentication data. The vulnerability affects only login operations within an active visualization session.

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

During concurrent login operations within an active visualization session, authentication credentials from one low-privileged user may be exposed to other users due to insufficient isolation of authentication data in memory or session handling. This is a race condition or improper session isolation flaw specific to visualization login operations.

MitigationImplement proper session isolation to ensure each concurrent login operation maintains separate authentication data, preventing credential leakage between user sessions.

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
VisualizationApplication
Affected:>= 1.0.0.0, < 4.10.0.0

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

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

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 Visualization version
    Locate the installed Codesys Visualization component and retrieve its version number from the product information, About dialog, or system registry if applicable
    Affected if Installed version falls within >= 1.0.0.0 and < 4.10.0.0 range
  2. Confirm Visualization component is in use
    Verify that the Codesys Visualization module or runtime component is installed and active in the environment
    Affected if Codesys Visualization is installed and operational
  3. Check for multi-user visualization environment
    Examine whether concurrent user sessions are possible or configured in the visualization environment (e.g., multiple clients, terminal services, or multi-user runtime access)
    Affected if Multiple users can access the visualization environment simultaneously or concurrently
  4. Review visualization login session isolation
    Inspect the runtime configuration or session management settings for the visualization component to determine if authentication data isolation between concurrent sessions is enforced
    Affected if Session isolation is not properly configured or credential data may be shared between concurrent users

User is affected if Codesys Visualization version is >= 1.0.0.0 and < 4.10.0.0, the visualization component is active, and multiple users can access concurrent sessions where authentication data may not be properly isolated between users.

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 4.10.0.0 or later
Fixed in 4.10.0.0
Interim mitigation

Implement proper session isolation to ensure each concurrent login operation maintains separate authentication data, preventing credential leakage between user sessions.

Recommended fix Moderate confidence

4.10.0.0 or later

  1. 1. Identify all CODESYS Visualization installations in the environment running versions >= 1.0.0.0 and < 4.10.0.0
  2. 2. Plan maintenance window for upgrade procedure
  3. 3. Backup current visualization configuration and project files
  4. 4. Download CODESYS Visualization version 4.10.0.0 or later from official vendor source
  5. 5. Stop all active visualization sessions and services
  6. 6. Install version 4.10.0.0 or newer following vendor installation guidelines
  7. 7. Restore configuration from backup if needed
  8. 8. Verify visualization login functionality works correctly
Caveat Review release notes for version 4.10.0.0 for any compatibility changes or deprecated features compared to your current version

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

Fix this in Visualization Scoped from the published advisory
  • Consultation4.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA3.0 h
25.0 hours of engineering $4,400
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Scan for this in your stack

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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-2026-0393 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