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Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-25787

CRITICAL · 9.1 CVSS v3.1 Published 2026-05-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
97/100
Remediation priority · Urgent
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
Affected devices do not properly validate and sanitize Technology Object (TO) name rendered on the "Motion Control Diagnostics" page of the web interface. This could allow an authenticated attacker who is authorized to download a TIA project into the product, to inject malicious scripts into the page. If a benign user with appropriate rights accesses the "Motion Control Diagnostics" parameters page, the malicious code would be executed in the scope of their web 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 · high confidence

This is a stored Cross-Site Scripting (XSS) vulnerability in the web interface of affected industrial devices. An authenticated attacker with TIA project download privileges can inject malicious JavaScript into the Technology Object (TO) name field. When other authorized users access the 'Motion Control Diagnostics' page, the unsanitized TO name is rendered in HTML, causing the attacker's script to execute in the victim's browser session.

MitigationImplement strict input validation for Technology Object names during project import/download and apply proper output encoding/sanitization before rendering any TO names on the Motion Control Diagnostics page.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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
High
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/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 TIA Portal installation and version
    Check the installed Siemens TIA Portal version by viewing the program in Add/Remove Programs (Windows) or checking the installation directory for version information. Compare your version against the affected range.
    Affected if The installed TIA Portal version is within the affected range and the web interface is enabled.
  2. Verify Motion Control Diagnostics web interface is enabled
    Check if the web-based Motion Control Diagnostics feature is enabled in the TIA Portal project settings or runtime configuration. This is typically accessible through the TIA Portal's web server configuration.
    Affected if The Motion Control Diagnostics web interface is enabled and accessible over the network.
  3. Confirm user accounts with TIA project download privileges exist
    Review the user management or project protection settings in TIA Portal to identify accounts that have permission to modify Technology Objects and download projects. Check the user roles and privileges configuration.
    Affected if There are authenticated users with TIA project download privileges who can access the web interface.
  4. Inspect Technology Object names for unsanitized content
    Access the Motion Control Diagnostics page via the web interface and examine how Technology Object names are displayed. Use browser developer tools or HTTP response inspection to observe if the TO name field reflects raw input without proper HTML encoding.
    Affected if The Technology Object names are displayed without proper output encoding, allowing script execution.
  5. Verify stored XSS payload execution
    If you have a TO with a test payload containing script tags in its name, access the Motion Control Diagnostics page and check if the JavaScript executes in your browser context.
    Affected if Malicious JavaScript embedded in the TO name field executes when other users view the Motion Control Diagnostics page.

A user is affected if they run a vulnerable TIA Portal version with the Motion Control Diagnostics web interface enabled and have users with TIA project download privileges accessing the exposed interface.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement strict input validation for Technology Object names during project import/download and apply proper output encoding/sanitization before rendering any TO names on the Motion Control Diagnostics page.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA3.0 h
19.0 hours of engineering $3,380
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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-2026-25787 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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