XperienceApplication · Kentico

CVE-2020-36889

MEDIUM · 5.4 CVSS v3.1 Published 2025-12-18
Fix available
A fix is available. Upgrade to after 12.0.90 or later.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable

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 stored cross-site scripting vulnerability in Kentico Xperience allows attackers to inject malicious scripts via error messages containing specially crafted object names. This allows malicious scripts to execute in users' browsers when administrators view error messages in the administration interface.

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 cross-site scripting vulnerability in Kentico Xperience allows attackers to inject malicious scripts through specially crafted object names that get stored in error messages. When administrators view these error messages in the administration interface, the embedded scripts execute in their browsers.

MitigationImplement proper input validation for object names and output encoding for error messages to neutralize malicious script execution; apply available vendor patches for Kentico Xperience.

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
XperienceApplication
Affected:<= 12.0.90

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
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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. Determine installed Kentico Xperience version
    Locate the Kentico Xperience installation and identify the version number. Common locations include the administration dashboard, assembly version info, or installer records. Compare your version against the affected range: <= 12.0.90
    Affected if Your installed version is 12.0.90 or lower
  2. Verify admin interface accessibility
    Confirm whether the Kentico Xperience administration interface (typically at /Admin or similar path) is accessible from the network. Check for exposed admin endpoints in your web server configuration
    Affected if The admin interface is accessible to unauthorized or untrusted users on the network
  3. Review error logs for unusual object names
    Examine Kentico Xperience error logs and event tracking data for entries containing object names with unexpected characters, tags, or script-like content. Focus on errors logged during object creation or manipulation
    Affected if Error logs contain object names with HTML, script tags, or JavaScript-like syntax
  4. Inspect stored error messages in the admin interface
    Access the Kentico Xperience administration interface and review any stored error messages, notifications, or event records that may contain user-supplied object names
    Affected if Stored error messages display unencoded content that could contain script tags

You are affected if your Kentico Xperience version is 12.0.90 or lower AND the admin interface is accessible, with potential evidence of unsanitized object names in error logs.

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
Upgrade available Upgrade to a release after 12.0.90
Interim mitigation

Implement proper input validation for object names and output encoding for error messages to neutralize malicious script execution; apply available vendor patches for Kentico Xperience.

Fix this in Xperience Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,984.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2020-36889 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2020-36889 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