An arbitrary file upload vulnerability in Umbraco CMS v16.3.3 allows attackers to execute arbitrary code by uploading a crafted PDF file. NOTE: this is disputed by the Supplier because the responsibility for file validation (as shown in the documentation) belongs to the system administrator who is implementing Umbraco CMS in their environment, not to Umbraco CMS itself.

Impact Within Umbraco Forms, configuring a malicious URL on the Webservice data source can result in Remote Code Execution. This affects all Umbraco Forms versions running on .NET Framework (up to and including version 8).

Patches The affected Umbraco Forms versions are all End-of-Life (EOL) and not supported anymore, hence no patches will be released. Upgrading to any of the currently supported versions (v13, v16 or v17) is recommended.

Workarounds If none of the configured Forms data sources uses the Webservice type, it can be safely excluded by adding the following code to the application. This will completely remove the option to select/use this data source within the Backoffice and thereby mitigate the vulnerability.

c# using Umbraco.Core.Composing; using Umbraco.Forms.Core.Providers; using Umbraco.Forms.Core.Providers.DatasourceTypes;

internal sealed class RemoveFormsWebserviceDataSourceTypeComposer : IUserComposer { public void Compose(Composition composition) => composition.WithCollectionBuilder<DataSourceCollectionBuilder>().Exclude<Webservice>(); }

Any Webservice data source that is configured and still in use should be replaced with a custom implementation instead, before applying the above code. If this is not feasible, the vulnerability can be minimized by revoking the 'Manage Data Sources' from any non-administrator user and/or inheriting from the default Umbraco.Forms.Core.Providers.DatasourceTypes.Webservice class and overriding the ValidateSettings() method to ensure only trusted URLs can be used.

References When upgrading to a supported version, please take the Forms version specific upgrade notes into account and check the CMS upgrade documentation. Content and schema can also be migrated straight to the latest version using Deploy export/import with migrations.

Implementation details on data sources are not extensively documented, but they follow the general Forms provider model and inherit from Umbraco.Forms.Core.FormDataSource.

A special thanks to Piotr Bazydlo (@chudyPB) of watchTowr for finding and disclosing this vulnerability

Umbraco CMS versions prior to 4.7.1 are vulnerable to unauthenticated remote code execution via the codeEditorSave.asmx SOAP endpoint, which exposes a SaveDLRScript operation that permits arbitrary file uploads without authentication. By exploiting a path traversal flaw in the fileName parameter, attackers can write malicious ASPX scripts directly into the web-accessible /umbraco/ directory and execute them remotely.

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

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.

Umbraco Forms version 4.0.0 up to and including 8.7.5 and below are vulnerable to a security flaw that could lead to a remote code execution attack and/or arbitrary file deletion. A vulnerability occurs because validation of the file extension is performed after the file has been stored in a temporary directory. By default, files are stored within the application directory structure at %BASEDIR%/APPDATA/TEMP/FileUploads/. Whilst access to this directory is restricted by the root web.config file, it is possible to override this restriction by uploading another specially crafted web.config file to the temporary directory. It is possible to exploit this flaw to upload a malicious script file to execute arbitrary code and system commands on the server.

Umbraco is a ASP.NET CMS. Under rare conditions a restart of Umbraco can allow unauthorized users access to admin-level permissions. This vulnerability was patched in versions 10.6.1, 11.4.2 and 12.0.1.

In Umbraco 7.3.8, there is SQL Injection in the backoffice/PageWApprove/PageWApproveApi/GetInpectSearch method via the nodeName parameter.

File upload vulnerability in Umbraco Forms v.8.7.0 allows unauthenticated attackers to execute arbitrary code via a crafted web.config and asp file.

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.

Umbraco Cloud 8.5.3 allows an authenticated file upload (and consequently Remote Code Execution) via the Install Packages functionality.

Umbraco before 7.4.0 allows remote attackers to bypass anti-forgery security measures and conduct cross-site request forgery (CSRF) attacks as demonstrated by editing user account information in the templates.asmx.cs file.

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.

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 PageLoad function in Umbraco.Web/umbraco.presentation/umbraco/dashboard/FeedProxy.aspx.cs in Umbraco before 7.4.0 allows remote attackers to conduct server-side request forgery (SSRF) attacks via the url parameter.

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.

Description A vulnerability has been identified in Umbraco Engage where certain API endpoints are exposed without enforcing authentication or authorization checks. The affected endpoints can be accessed directly over the network without requiring a valid session or user credentials. By supplying a user-controlled identifier parameter (e.g., ?id=), an attacker can retrieve sensitive data associated with arbitrary records.

Because no access control validation is performed, the endpoints are vulnerable to enumeration attacks, allowing attackers to iterate over identifiers and extract data at scale.

Impact An unauthenticated attacker can retrieve sensitive Engage-related data by directly querying the affected API endpoints. The vulnerability allows arbitrary record access through predictable or enumerable identifiers.

The confidentiality impact is considered high. No direct integrity or availability impact has been identified.

The scope of exposed data depends on the deployment but may include analytics data, tracking data, customer-related information, or other Engage-managed content.

Patches The vulnerability affects both v16 and v17. Patches have already been released. Users are advised to update to 16.2.1 or 17.1.1

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.

This affects all versions of package UmbracoForms. When using the default configuration for upload forms, it is possible to upload arbitrary file types. The package offers a way for users to mitigate the issue. The users of this package can create a custom workflow and frontend validation that blocks certain file types, depending on their security needs and policies.

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.

Description A privilege escalation vulnerability has been identified in Umbraco CMS. Under certain conditions, authenticated backoffice users with permission to manage users, may be able to elevate their privileges due to insufficient authorization enforcement when modifying user group memberships.

The affected functionality does not properly validate whether a user has sufficient privileges to assign highly privileged roles.

Impact An authenticated backoffice user may be able to escalate their privileges to Administrator level.

Successful exploitation results in full administrative control of the affected Umbraco CMS instance, including unrestricted access to content, user management, and configuration settings.

The impact is significantly mitigated by the fact that this can only be exploited by a user that has already been given access to the "Users" section in the CMS. For most Umbraco setups, such users are already also "Administrators".

Patches The issue is patched in 16.5.1 and 17.2.2.

Workarounds There is no workaround other than upgrading for setups where they want to have users with permission for the "Users" section without also being content with those users also being part of the "Administrators" user group.

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.

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.

Umbraco CMS v8.14.1 contains a server-side request forgery vulnerability that allows attackers to manipulate baseUrl parameters in multiple dashboard and help controller endpoints. Attackers can craft malicious requests to the GetContextHelpForPage, GetRemoteDashboardContent, and GetRemoteDashboardCss endpoints to trigger unauthorized server-side requests to external hosts.

Description An authenticated backoffice user with access to Settings can inject malicious HTML into property type descriptions. Due to an overly permissive attributeNameCheck configuration (/.+/) in the UFM DOMPurify instance, event handler attributes such as onclick and onload, when used within Umbraco web components (umb-, uui-, ufm-) were not filtered.

Impact As property type descriptions support Markdown/HTML via the UFM rendering pipeline, injected event handlers are rendered in the backoffice interface, resulting in a stored XSS affecting other backoffice users.

Patches The issue is patched in 16.5.1 and 17.2.2.

Workarounds There is no workaround other than upgrading.

References https://docs.umbraco.com/umbraco-cms/reference/umbraco-flavored-markdown

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

Withdrawn Advisory This advisory has been withdrawn because the issue is a documented security. This link is maintained to preserve external references. For more information, see https://github.com/github/advisory-database/pull/5270.

Original Advisory A stored cross-site scripting (XSS) vulnerability in Umbraco CMS v14.3.1 allows attackers to execute arbitrary web scripts or HTML via a crafted payload.

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 It's possible for an authenticated backoffice-user to enumerate and traverse paths/files on the systems filesystem and read their contents, on Mac/Linux Umbraco installations using Forms. As Umbraco Cloud runs in a Windows environment, Cloud users aren't affected.

Patches This issue affects versions 16 and 17 of Umbraco Forms and is patched in 16.4.1 and 17.1.1

Workarounds If upgrading is not immediately possible, users can mitigate this vulnerability by: Configuring a WAF or reverse proxy to block requests containing path traversal sequences (../, ..\) in the fileName parameter of the export endpoint Restricting network access to the Umbraco backoffice to trusted IP ranges Blocking the /umbraco/forms/api/v1/export endpoint entirely if the export feature is not required

However, upgrading to the patched version is strongly recommended.

References Credit to Kevin Joensen from Baldur Security for finding this vulnerability

An authenticated path traversal vulnerability exists during package installation in Umbraco CMS <= 8.9.1 or current, which could result in arbitrary files being written outside of the site home and expected paths when installing an Umbraco package.