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

CVE-2026-25786

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 PLC/station name rendered on the "communication" parameters 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 "communication" 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 · moderate confidence

A stored XSS vulnerability exists in the web interface of affected devices where the PLC/station name field on the communication parameters page is not properly validated or sanitized. An authenticated attacker with TIA project download privileges can inject malicious JavaScript that persists and executes in the sessions of other authorized users who access the communication parameters page.

MitigationImplement strict input validation and output encoding for all PLC/station name fields on the communication parameters page; restrict TIA project download permissions to trusted personnel until vendor patches are available.

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. Confirm web interface is enabled and accessible
    Access the device web interface via HTTP/HTTPS. If the login page or device dashboard loads, the web interface is active.
    Affected if The web interface is accessible without additional configuration changes.
  2. Identify user account privileges
    Log into the web interface and navigate to user accounts, roles, or permissions settings. Verify if the account has 'TIA project download' or equivalent privileges assigned.
    Affected if The logged-in account possesses TIA project download privileges, which are required to exploit this vulnerability.
  3. Locate PLC/station name configuration field
    Within the web interface, navigate to the communication parameters or settings page where PLC or station names are configured. This is typically found under project settings, communication setup, or network configuration sections.
    Affected if The communication parameters page with PLC/station name fields is accessible in the interface.
  4. Inspect stored PLC/station name values for script content
    View the current PLC/station name entries on the communication parameters page. Check the page source or use browser developer tools to examine if the stored values contain HTML script tags, javascript:, or other XSS payload patterns.
    Affected if The PLC/station name field contains unsanitized script content that renders as executable code or appears as raw HTML/script tags in the page.
  5. Compare installed firmware/software version
    Locate the device firmware version or software version number in the web interface system info, about page, or diagnostics section. Compare this against the affected version range for this CVE.
    Affected if The installed version falls within the affected version range provided for this CVE.

A user is affected if the web interface is accessible, their account has TIA project download privileges, and the PLC/station name field on the communication parameters page contains unsanitized script content or the firmware version matches the affected range.

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 and output encoding for all PLC/station name fields on the communication parameters page; restrict TIA project download permissions to trusted personnel until vendor patches are available.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,800
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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-2026-25786 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