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Medium

Cross-site scripting from dynamic options in the multiselect field

  • Disclosed: 29.08.2022
  • Updated: 11.10.2026 10:22

Introduction

Cross-site scripting (XSS) is a type of vulnerability that allows to execute any kind of JavaScript code inside the Panel session of the same or other users. In the Panel, a harmful script can for example trigger requests to Kirby's API with the permissions of the victim.

Such vulnerabilities are critical if you might have potential attackers in your group of authenticated Panel users. They can escalate their privileges if they get access to the Panel session of an admin user. Depending on your site, other JavaScript-powered attacks are possible.

Impact

The multiselect field allows to select tags from an autocompleted list. Unfortunately, the Panel in Kirby 3.5 used HTML rendering for the raw option value.

This allowed attackers with influence on the options source (e.g. content of sibling pages or an API endpoint) to inject HTML code. If a page in the Panel that uses the manipulated multiselect options was visited by a victim and the victim opened the autocomplete dropdown, the victim's browser will then have rendered this malicious HTML code.

You are not affected by this vulnerability if you don't use the multiselect field or only use it with options that cannot be manipulated by attackers.

Patches

The problem has been patched in Kirby 3.5.8.1. Please update to this or a later version to fix the vulnerability.

Workarounds

We recommend to update to the patch release. If you cannot update immediately, you can work around the issue by disabling the multiselect field. This can be done by uncommenting this field from all your blueprints.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Composer package getkirby/cms < 3.5.8.1 3.5.8.1

References

CVSS score 5.9/10
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N
Weakness (CWE)
CWE-79
Platform
Composer
Package
getkirby/cms
Disclosed
29.08.2022
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-3f89-869f-5w76 - CC BY 4.0

Vulnerability history: getkirby/cms

All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (51) in the archive
Total entries
51
First → latest
12.2020 09.2026
Without a fix
2
Exploited in attacks
0

Severity breakdown

  • Critical 1
  • High 19
  • Medium 30
  • Low 1

Disclosures per year

Severity:
  1. Kirby: File upload permissions are not checked during processing of chunk data
    High CVE-2026-71415 >= 5.0.0, < 5.5.2 5.5.2
  2. Kirby: Access to image files and limited access to JSON files outside of the site root via path traversal in the media handling
    High CVE-2026-75594 < 4.9.5, >= 5.0.0, < 5.5.2 4.9.5, 5.5.2
  3. Kirby: `pages.access` permission is not checked in the `site/find` REST API route
    High CVE-2026-54005 < 4.9.4, >= 5.0.0-alpha.1, < 5.4.4 4.9.4, 5.4.4
  4. Kirby: External Initialization of the Panel on reverse proxy setups with the `Forwarded` header
    Critical CVE-2026-54003 < 4.9.4, >= 5.0.0-alpha.1, < 5.4.4 4.9.4, 5.4.4
  5. Kirby: Cross-site scripting (XSS) from incomplete HTML/XML sanitization in `Dom::sanitize()`
    High CVE-2026-54002 < 4.9.4, >= 5.0.0-alpha.1, < 5.4.4 4.9.4, 5.4.4
  6. Kirby: Self cross-site scripting (self-XSS) in the writer field
    High CVE-2026-49276 < 4.9.4, >= 5.0.0-alpha.1, < 5.4.4 4.9.4, 5.4.4
  7. Kirby CMS vulnerable to cross-site scripting (XSS) from links in KirbyTags and image blocks in the site frontend
    High CVE-2026-45368 < 4.9.1, >= 5.0.0, < 5.4.1 4.9.1, 5.4.1
  8. Kirby CMS has pre-authentication path traversal and PHP file inclusion during user lookup
    High CVE-2026-44177 >= 5.3.0, < 5.4.1 5.4.1
  9. Kirby CMS vulnerable to cross-site scripting (XSS) from list field content in the site frontend
    High CVE-2026-44175 < 4.9.1, >= 5.0.0, < 5.4.1 4.9.1, 5.4.1
  10. Kirby CMS has an Arbitrary Method Call via REST API Search and Collection Query Endpoints
    High CVE-2026-44174 < 4.9.1, >= 5.0.0, < 5.4.1 4.9.1, 5.4.1
  11. Kirby CMS's read access to site, user and role information is not gated by permissions
    High CVE-2026-42069 < 4.9.0, >= 5.0.0, < 5.4.0 4.9.0, 5.4.0
  12. Kirby CMS's `pages.access/list` and `files.access/list` permissions are not consistently checked in the Panel and REST API
    High CVE-2026-42137 < 4.9.0, >= 5.0.0, < 5.4.0 4.9.0, 5.4.0
  13. Kirby is vulnerable to authorization bypass during page, file and user creation via blueprint injection
    High CVE-2026-41325 < 4.9.0, >= 5.0.0, < 5.4.0 4.9.0, 5.4.0
  14. Kirby has Server-Side Template Injection (SSTI) via double template resolution in option rendering
    High · 8.1 CVE-2026-34587 < 4.9.0, >= 5.0.0, < 5.4.0 4.9.0, 5.4.0
  15. Kirby has insufficient permission checks in the language settings
    High · 8.1 CVE-2024-41964 < 3.6.6.6, >= 3.7.0, < 3.7.5.5, >= 3.8.0, < 3.8.4.4, >= 3.9.0, < 3.9.8.2, >= 3.10.0, < 3.10.1.1, >= 4.0.0, < 4.3.1 3.6.6.6, 3.7.5.5, 3.8.4.4, 3.9.8.2, 3.10.1.1, 4.3.1
  16. Field injection in the KirbyData text storage handler
    High · 7.1 CVE-2023-38488 < 3.5.8.3, >= 3.6.0, < 3.6.6.3, >= 3.7.0, < 3.7.5.2, >= 3.8.0, < 3.8.4.1, >= 3.9.0, < 3.9.6 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, 3.9.6
  17. Insufficient Session Expiration after a password change
    High · 7.3 CVE-2023-38489 < 3.5.8.3, >= 3.6.0, < 3.6.6.3, >= 3.7.0, < 3.7.5.2, >= 3.8.0, < 3.8.4.1, >= 3.9.0, < 3.9.6 3.5.8.3, 3.6.6.3, 3.7.5.2, 3.8.4.1, 3.9.6
  18. Cross-site scripting from content entered in the tags and multiselect fields
    High · 7.1 ghsa-rv3r-vqjj-8c76 >= 3.5.7, < 3.5.8.1, >= 3.6.0, < 3.6.6.1, >= 3.7.0, < 3.7.4 3.5.8.1, 3.6.6.1, 3.7.4
  19. Cross-site scripting from dynamic options in the multiselect field this entry
    Medium · 5.9 CVE-2022-36037 < 3.5.8.1 3.5.8.1
  20. Cross-site scripting (XSS) from field and configuration text displayed in the Panel
    High · 7.1 CVE-2021-32735 < 3.5.7 3.5.7
  21. Cross-site scripting (XSS) from unsanitized uploaded SVG files in Kirby
    High · 7.6 CVE-2021-29460 < 3.5.4 3.5.4

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