CVE-2026-108924 is an authorization bypass vulnerability in the getkirby Kirby CMS affecting versions 4.9.0 through 4.9.5 and 5.5.0 through 5.5.3. The issue exists in the OptionsQuery::resolve function within the Dynamic Option Generation component. This vulnerability allows remote attackers to bypass authorization controls. Upgrading to versions 4.9.6 or 5.6.0 resolves the issue.
Kirby is an open-source content management system. Prior to 4.9.5 and 5.5.2, depending on the release line, Kirby's media handler in src/Cms/Media.php allowed Kirby\Cms\Media::thumb() to append a path-bearing filename to a validated parent media directory. On nginx, PHP's built-in server, or Apache with AllowEncodedSlashes enabled, a remote attacker could submit encoded slash characters such as %2f in the filename and traverse outside the parent's media directory. Differences between responses for existing and nonexistent thumbnail configurations disclosed whether an arbitrary .json file existed, and a .json file containing a valid filename key could cause the referenced image to be returned and the job file to be deleted. The related file::version path in src/Filesystem/Asset.php also accepted ../ sequences outside the intended index root. This issue is fixed in versions 4.9.5 and 5.5.2.
Kirby is an open-source content management system. Prior to 4.9.5 and 5.5.2, depending on the release line, Kirby's media handler used incomplete filesystem containment checks in src/Filesystem/Dir.php and src/Filesystem/F.php through Kirby\Filesystem\Dir::realpath() and Kirby\Filesystem\F::realpath(). The checks accepted a sibling directory whose path shared the intended root's string prefix, such as /var/www/site2 next to /var/www/site, because they did not require an exact match or a DIRECTORY_SEPARATOR boundary. A remote attacker could use Kirby\Cms\Media::thumb() to create and access thumbnails from image files in a PHP-readable sibling directory when that directory contained a valid .json thumbnail job file, potentially exposing staging sites, backups, or other internal sites and deleting the job file during processing. This issue is fixed in versions 4.9.5 and 5.5.2.
Kirby is an open-source content management system. From 5.0.0 until 5.5.2, Kirby's REST API chunk upload handler in src/Api/Upload.php did not run the relevant upload authorization preflight in Kirby\Api\Upload::process() before Kirby\Api\Upload::processChunk() persisted chunk data. An authenticated user with the access.panel permission enabled but with files.create, files.replace, and user/users.update permissions disabled could submit requests with an Upload-Length header and leave unfinished chunks in site/cache/.uploads for 24 hours. Repeating this process could consume attacker-controlled temporary storage, prevent other users from uploading files, or prevent site logic from storing data, although final permission checks still prevented unauthorized files from reaching the content or site/accounts directories. This issue is fixed in version 5.5.2.
Kirby is an open-source content management system. Prior to 4.9.5 and from 5.0.0 through 5.5.1, the REST API error handler can return unsanitized PHP error messages that expose the full filesystem path of the Kirby installation to unauthenticated API users. This vulnerability affects all Kirby sites that have not disabled the REST API with the 'api' => false option. This issue is fixed in versions 4.9.5 and 5.5.2.
Kirby is an open-source content management system. In versions prior to 4.9.1 and 5.4.1, the underlying URL methods for the KirbyTags and image blocks components did not filter out malicious URL values that resolve to script execution. The vulnerability affects four first-party Kirby renderers that produce `<a href="…">` output from editor-supplied field values: the (`link: …)` KirbyTag, the `link`: parameter of the `(image: …)` KirbyTag when it does not resolve to a known file or `self`, the `link` field of the built-in image block, and the HTML importer for the `blocks` field (which accepted the same malicious input as the image block `link` field). While simple `avascript:` URLs were already deactivated by treating them as a relative path and prepending a single slash to the URL, the use of URLs of the format `javascript://x%0A…` bypasses this protection. The `vbscript:`, `data:`, `livescript:`, `mocha:` and `jar:` schemes are affected by the same underlying gap. This issue has been fixed in versions 4.9.1 and 5.4.1.
Kirby is an open-source content management system. In versions prior to 4.9.1 and 5.4.1, the content-locking feature returned lock information without checking the requesting user's access permissions. Kirby's Panel includes a content-locking feature that records which user currently has a model open for editing. This lock prevents conflicting edits by multiple users and displays the locking user's identity in the Panel UI so other users know who to contact. Internally, the locking user's email address and identifier are included in every Panel view payload and in error responses returned when a user attempts to edit a model that is currently locked by another user. This allowed a low-privilege authenticated Panel user, whose role was configured with users.access: false or users.list: false, to learn the email address and identifier of any user who currently had a model open for editing in the Panel, including administrators and other higher-privilege users. Content locks are active for a configurable window (10 minutes by default). The email address can allow admin account enumeration, target phishing, and feed credential-stuffing attacks against the Kirby installation or other sites. The internal user ID can be cross-referenced with other endpoints once the requester has obtained a higher privilege through unrelated means. This issue has been fixed in versions 4.9.1 and 5.4.1.
Kirby is an open-source content management system. In versions prior to 4.9.1 and 5.4.1, Kirby did not securely sanitize the contents of the list field on save, leaving it vulnerable to cross-site scripting (XSS). Kirby's list field stores its formatted content as HTML, and unlike other field types, its HTML special characters cannot be escaped without losing the formatting. Sanitization was only enforced client-side in the Panel, while the server did not sanitize the content on save. As a result, an attacker could bypass the Panel and send malicious HTML directly to Kirby's API, storing unsanitized markup in the content file. That markup would then be rendered on the site frontend and executed in the browsers of site visitors and logged-in users browsing the site, resulting in persistent XSS. This issue has been fixed in versions 4.9.1 and 5.4.1.
Kirby is an open-source content management system. Versions prior to 4.9.1 and 5.4.1 do not check the `pages.access` permission during page draft rendering. Permissions are defined for each user role in the user blueprint (site/blueprints/users/...). It is also possible to customize the permissions for each target model in the model blueprints (such as in site/blueprints/pages/...) using the options feature. The permissions and options together control the authorization of user actions. Kirby provides the pages.access and pages.list permissions (among others). The list permission controls whether affected models appear in lists throughout the Panel and REST API. The access permission has the same effect but also disables direct access to the affected models. This vulnerability affects the path resolver for the main CMS router. The resolver takes an input path from the requested URL and determines which model (page or file) should be rendered. When a path is requested that points to a page draft, the resolver checks that the request either contains a valid preview token or is authenticated by a valid user. In affected releases, Kirby allowed page drafts to be rendered if any valid user was authenticated, even if that user did not have access to the specific page model. Authenticated attackers with knowledge of the full path to an existing page draft could then access the rendered frontend page. This could lead to the disclosure of sensitive information, e.g. ahead of the launch of a new product or post. This issue has been fixed in versions 4.9.1 and 5.4.1.
Kirby is an open-source content management system. In versions 5.3.0 and above but prior to 5.4.1, Kirby did not correctly validate the provided user ID, resulting in a path traversal vulnerability. Version 5.3.0 introduced a performance improvement to the Users collection that loaded user objects lazily when first needed. Users were queried by their ID, which was then used to locate the corresponding account directory under site/accounts. This affected the authentication API (accessible to unauthenticated requests), the users API (accessible only to authenticated users), and any other place that uses $users->find() to look up an individual user by a request-provided email or ID. As a result, an attacker could trigger arbitrary PHP file inclusion of files named index.php (for example, the main PHP files of plugins), the impact of which depends on the logic those files contain. It also allowed probing for the existence of arbitrary directories on the server, letting attackers fingerprint the server and site setup, including installed plugins and the content structure. This issue has been fixed in version 5.4.1.
Kirby is an open-source content management system. Prior to 4.9.1 and 5.4.1, Kirby did not validate the model attributes that were used in its collection queries, allowing attackers to include arbitrary model methods in their queries. This includes methods with sensitive data such as password() (disclosing the password hash) or root() (disclosing the absolute filesystem path on the server) as well as methods that perform impactful actions such as loginPasswordless() (causing a privilege escalation to another user) or delete() (deleting all queried models in one go if the authenticated user has appropriate permissions). This issue has been fixed in versions 4.9.1 and 5.4.1.
Kirby is an open-source content management system. Prior to 4.9.4 and 5.4.4, Kirby sites using the writer field in any blueprint allowed a scripting link to be included as the target of a link or email link in writer mark components, making the target clickable by the user who entered it and enabling self cross-site scripting in the Panel. This issue is fixed in versions 4.9.4 and 5.4.4.
Kirby is an open-source content management system. Prior to 4.9.4 and 5.4.4, Kirby sites where a role has the pages.access permission disabled allowed authenticated users who know or guess page IDs or UUIDs to retrieve page information, including full content and metadata, for arbitrary published pages through the /api/site/find route without authorization to access those pages. This issue is fixed in versions 4.9.4 and 5.4.4.
Kirby is an open-source content management system. Prior to 4.9.4 and 5.4.4, Kirby sites and plugins using the Kirby Http Remote class, including Remote::request(), Remote::get(), and Remote::post(), to send outgoing HTTP requests with untrusted data in the headers option could allow newline characters in a header value to inject a separate unintended request header to the remote service. This issue is fixed in versions 4.9.4 and 5.4.4.
Kirby is an open-source content management system. Prior to 4.9.4 and 5.4.4, Kirby sites with content.fileRedirects enabled could redirect unauthenticated clean file URL requests for files stored in top-level draft pages to physical media URLs without checking page access permissions or preview tokens, leading to disclosure of draft file contents. This issue is fixed in versions 4.9.4 and 5.4.4.
Kirby is an open-source content management system. Prior to 4.9.4 and 5.4.4, Kirby sites using the pages field with roles that have the pages.access permission disabled allowed authenticated users to provide an inaccessible parent page or site to the page picker backend and confirm arbitrary page existence and retrieve title field values. This issue is fixed in versions 4.9.4 and 5.4.4.
Kirby is an open-source content management system. Prior to 4.9.4 and from 5.4.4, Kirby sites with no configured user accounts that run on publicly accessible servers behind a reverse proxy setting the Forwarded, X-Client-IP, or X-Real-IP request header could allow remote attackers to install the Panel and create the first admin user because local-IP checks trusted those headers incorrectly. This issue is fixed in versions 4.9.4 and 5.4.4.
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.
Kirby is an open-source content management system. Prior to versions 4.9.0 and 5.4.0, user avatar creation, replacement and deletion are not gated by user update permissions. This issue has been patched in versions 4.9.0 and 5.4.0.
Kirby is an open-source content management system. Prior to versions 4.9.0 and 5.4.0, `pages.access/list` and `files.access/list` permissions are not consistently checked in the Panel and REST API. This issue has been patched in versions 4.9.0 and 5.4.0.