dbcve.org
Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-54002

HIGH · 8.5 CVSS v4.0 Published 2026-07-09
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
89/100
Remediation priority · High
Remotely reachable Patch available 6 weeks old

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
Kirby is an open-source content management system. Prior to 4.9.4 and 5.4.4, Kirby sites and plugins that use the writer or list fields or call Dom::sanitize(), Sane::sanitize(), Sane::Html::sanitize(), Sane::Svg::sanitize(), Sane::Xml::sanitize(), Sane::sanitizeFile(), or file sanitizeContents() with untrusted input allow malicious markup injected as children of an unknown HTML or XML tag to pass through Dom::sanitize() without being correctly sanitized, causing stored cross-site scripting. This issue is fixed in versions 4.9.4 and 5.4.4.

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

Kirby CMS versions prior to 4.9.4 and 5.4.4 contain a stored XSS vulnerability where malicious markup injected as children of unknown HTML/XML tags bypasses the Dom::sanitize() function. The vulnerability is triggered when using writer or list fields or calling specific sanitization methods (Dom::sanitize(), Sane::sanitize(), Sane::Html::sanitize(), Sane::Svg::sanitize(), Sane::Xml::sanitize(), Sane::sanitizeFile(), or sanitizeContents()) with untrusted input.

MitigationUpdate Kirby to version 4.9.4 or 5.4.4 to patch the sanitization bypass. Audit all instances where the affected fields and sanitization functions process user-submitted content.

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
Low
Authentication
X
User interaction
P
Scope
X

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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 Kirby CMS installation
    Locate the Kirby directory and check for the existence of the composer.json or index.php file that would indicate a Kirby installation.
    Affected if Kirby CMS is present on the system.
  2. Determine installed Kirby version
    Open the composer.json file in the Kirby root directory and locate the 'version' field under 'require', or check the Kirby扶持程序 version file if available in the system.
    Affected if The installed version is prior to 4.9.4 or 5.4.4.
  3. Check for writer field usage
    Search Kirby blueprint files (typically in /site/blueprints/) for field definitions containing 'type: writer' or 'writer:' configuration.
    Affected if Writer fields are defined and in use on the site.
  4. Check for list field usage
    Search Kirby blueprint files for field definitions containing 'type: list' or 'list:' configuration.
    Affected if List fields are defined and in use on the site.
  5. Check for custom sanitization calls
    Search custom PHP code in the /site/ directory for calls to Dom::sanitize(), Sane::sanitize(), Sane::Html::sanitize(), or similar sanitization methods.
    Affected if Custom code invokes any of the affected Dom::sanitize() or Sane::* sanitization methods with untrusted input.

You are affected if you are running any Kirby version prior to 4.9.4 or 5.4.4 AND your site uses writer fields, list fields, or custom code that calls the affected sanitization methods with untrusted input.

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
Patch available Apply the vendor patch
Vendor patch github.com →
Interim mitigation

Update Kirby to version 4.9.4 or 5.4.4 to patch the sanitization bypass. Audit all instances where the affected fields and sanitization functions process user-submitted content.

Recommended fix High confidence

Kirby 4.9.4 for 4.x users or Kirby 5.4.4 for 5.x users

  1. 1. Identify your current Kirby CMS version by checking the composer.json file or thekirby/composer.json in your project
  2. 2. If you are running Kirby 4.x (versions below 4.9.4), upgrade to version 4.9.4
  3. 3. If you are running Kirby 5.x (versions below 5.4.4), upgrade to version 5.4.4
  4. 4. Run composer update getkirby/kirby --with-all-dependencies to apply the update
  5. 5. Clear any application caches after upgrading
  6. 6. Test the application to verify the XSS fix is working correctly
Caveat Review the Kirby changelog for the relevant release to check for any breaking changes in your specific version

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
Get the patch applied

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.

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-2026-54002 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