Impact Authenticated users to the Umbraco backoffice are able to craft management API request that exploit a path traversal vulnerability to upload files into a incorrect location.

Patches The issue affects Umbraco 14+ and is patched in 14.3.4 and 15.3.1.

Workarounds Umbraco supports the configuration of allowed and disallowed file extensions. Using these options to allow only necessary file extensions significantly reduces the scope of the vulnerability.

Impact Via a manipulated API request it's possible to upload a file that doesn't adhere with the configured allowable file extensions.

Patches Patched in 15.4.2 and 16.0.0.

Workarounds None available.

Impact

Based on an analysis of response codes and timing of Umbraco 14+ management API responses, it's possible to determine whether an account exists.

Patches

Patched in 14.3.2 and 15.1.2.

Workarounds

None available.

Impact Authenticated users are able to exploit an XSS vulnerability when viewing certain localized backoffice components.

Patches Will be patched in 14.3.2 and 15.1.2.

Note: This issue was reported by Pratik Patil from NetSPI @Nexusss-ppatil

Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-69cg-w8vm-h229. This link is maintained to preserve external references.

Original Description

A vulnerability was found in Umbraco CMS 12.3.6. It has been classified as problematic. Affected is an unknown function of the file /Umbraco/preview/frame?id{} of the component Dashboard. The manipulation of the argument culture leads to cross site scripting. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used.

Impact Stored Cross-site scripting (XSS) enable attackers that have access to backoffice to bring malicious content into a website or application.

Affected versions Umbraco CMS >= 8.00

Patches This is fixed in 8.18.13, 10.8.4, 12.3.7, 13.1.1 by implementing IHtmlSanitizer

Impact Failing webhooks logs are available when solution is not in debug mode. Those logs can contain information that is critical. Affected Versions Umbraco versions 13.0.0 - 13.1.1

Patches 13.1.1

Workarounds Disabling webhooks functionality.

Impact A user enumeration attack is possible.

Affected versions Umbraco 10 with access to the native login screen

Patches This is fixed in 10.8.5

Workarounds Disabling the native login screen, by exclusively use external logins.

Impact Umbraco have an endpoint that is vulnerable to open redirects. The endpoint is protected so it requires the user to be signed into backoffice, before the vulnerability is exposed.

Affected Version

\>= 8.18.5, >= 10.5.0, >= 12.0.0, >= 13.0.0

Patches 8.18.14, 10.8.6, 12.3.10, 13.3.1

Umbraco CMS 4.11.8 through 7.15.10, and 7.12.4, allows Remote Code Execution by authenticated administrators via msxsl:script in an xsltSelection to developer/Xslt/xsltVisualize.aspx.

Impact An improper access control issue has been identified, allowing low-privilege users to access the webhook API and retrieve information that should be restricted to users with access to the settings section

Impact The Backoffice displays the logout page with a session timeout message before the server session has fully expired, causing users to believe they have been logged out approximately 30 seconds before they actually are.

Impact There is a potential risk of code execution for Backoffice users when they “preview” SVG files in full screen mode.

Workarounds Server-side file validation is available to strip script tags from file's content during the file upload process.

Impact During an explicit sign-out, the server session is not fully terminated.

Impact This can be leveraged to gain access to higher-privilege endpoints, e.g. if you get a user with admin privileges to run the code, you can potentially elevate all users and grant them admin privileges or access protected content.

Patches Will be patched in 14.3.1 and 15.0.0.

Workarounds Ensure that access to the Dictionary section is only granted to trusted users.

Impact A brute force exploit that can be used to collect valid usernames is possible.

Explanation of the vulnerability It's a brute force exploit that can be used to collect valid usernames by using the “forgot password” function when trying to log into the Backoffice. If the username/email is known, it is easier to find the corresponding password. If an email address that was already used and registered by a user, is provided as an input, the server internal processing time takes longer. If the email address does not exist in the database of the registered users, the server would respond immediately.

Impact Backoffice users with permissions to create packages can use path traversal and thereby write outside of the expected location.

Explanation of the vulnerability The “Package” section in Umbraco Backoffice allows a logged in user to write folders outside of the default package directory.

Impact Some endpoints in the Management API can return stack trace information, even when Umbraco is not in debug mode.

Explanation of the vulnerability Management API endpoints leaked stack traces in case of Internal server errors, no matter if the debug setting was disabled.

E.g. when paging with negative numbers in some apis

Impact As an authenticated user one can access a few unintended endpoints

Explanation of the vulnerability Few endpoints in Umbraco Management API was not protected by a specific section. These just required you to be authenticated. Due to the fact that a member is also just authenticated, it was possible to get info from these endpoints using a member token.

Persistent cross-site scripting (XSS) vulnerability in Umbraco CMS 7.12.3 allows authenticated users to inject arbitrary web script via the Header Name of a content (Blog, Content Page, etc.). The vulnerability is exploited when updating or removing public access of a content.

Within the Umbraco CMS, a configuration element named "UmbracoApplicationUrl" (or just "ApplicationUrl") is used whenever application code needs to build a URL pointing back to the site. For example, when a user resets their password and the application builds a password reset URL or when the administrator invites users to the site. For Umbraco versions less than 9.2.0, if the Application URL is not specifically configured, the attacker can manipulate this value and store it persistently affecting all users for components where the "UmbracoApplicationUrl" is used. For example, the attacker is able to change the URL users receive when resetting their password so that it points to the attackers server, when the user follows this link the reset token can be intercepted by the attacker resulting in account takeover.

The password reset component deployed within Umbraco uses the hostname supplied within the request host header when building a password reset URL. It may be possible to manipulate the URL sent to Umbraco users when so that it points to the attackers server thereby disclosing the password reset token if/when the link is followed. A related vulnerability (CVE-2022-22690) could allow this flaw to become persistent so that all password reset URLs are affected persistently following a successful attack. See the AppCheck advisory for further information and associated caveats.

Impact Backoffice users with send for approval permission but not publish permission are able to publish in some scenarios.

Explanation of the vulnerability Backoffice users without permission to publish content, but only to send for approval, can bypass the restriction by modifying the request body of the "Send for Approval" request.

Impact Cross-site scripting (XSS) enable attackers to bring malicious content into a website or application.

Explanation of the vulnerability

A DOM-XSS can be exploited when users are successfully logging into the Backoffice.

Impact A user with access to the backoffice can upload SVG files that include scripts. If the user can trick another user to load the media directly in a browser, the scripts can be executed.

Workaround Implement the server side file validation https://docs.umbraco.com/umbraco-cms/reference/security/serverside-file-validation

or

Serve all media from an different host (e.g cdn) that where umbraco is hosted

The FeedProxy.aspx script in Umbraco 4.7.0 allows remote attackers to proxy requests on their behalf via the "url" parameter.

The update function in umbraco.webservices/templates/templateService.cs in the TemplateService component in Umbraco CMS before 6.0.4 does not require authentication, which allows remote attackers to execute arbitrary ASP.NET code via a crafted SOAP request.

Umbraco before 7.2.0 has a remote PHP code execution vulnerability because Umbraco.Web.UI/config/umbracoSettings.Release.config does not block the upload of .php files.

XML external entity (XXE) vulnerability in Umbraco CMS before 7.7.3 allows attackers to obtain sensitive information by reading files on the server or sending TCP requests to intranet hosts (aka SSRF), related to Umbraco.Web/umbraco.presentation/umbraco/dialogs/importDocumenttype.aspx.cs.

Cross-site scripting (XSS) vulnerability in Umbraco CMS before 7.7.3 allows remote attackers to inject arbitrary web script or HTML via the "page name" (aka nodename) parameter during the creation of a new page, related to Umbraco.Web.UI/umbraco/dialogs/Publish.aspx.cs and Umbraco.Web/umbraco.presentation/umbraco/dialogs/notifications.aspx.cs.