GHSA-2qjj-h6wp-c7h7 CVE-2026-46616

Umbraco.Cms: Open Redirect Vulnerability in Surface Controllers

Medium NuGet

Severity: 5.4 / 10; Medium · CVSS 3.1
Exploit chance (EPSS): 0.18%; Chance of exploitation in the next 30 days. Higher than 7.53% of scored vulnerabilities.
Known exploited: No; Not in CISA's catalog
Weakness: CWE-601 URL Redirection to Untrusted Site ('Open Redirect')
Fix: 13.14.0; Upgrade Umbraco.Cms to this version or later

Description

Impact

Some of the Surface Controllers in the CMS provide to support member related operations fail to validate redirect URLs, making Razor templates that derive 'RedirectUrl' from user-controlled query parameters vulnerable to malicious redirect attacks.

Patches

The issue is resolved in versions 17.4.0 and 13.14.0.

Workarounds

If users cannot upgrade immediately, they can mitigate the issue in their own site by ensuring every Razor form that posts to UmbLoginStatusController, UmbProfileController or UmbRegisterController passes a concrete, trusted RedirectUrl into Html.BeginUmbracoForm's route values.

For example:

  @using (Html.BeginUmbracoForm<UmbLoginStatusController>(
      "HandleLogout",
      new { RedirectUrl = Model.Url() }))
  {
      <button type="submit">Log out</button>
  }

Resources

https://github.com/umbraco/Umbraco-CMS/pull/22565 https://github.com/umbraco/Umbraco-CMS/pull/22561

Affected versions

NuGet

Package	Vulnerable	Fixed in
Umbraco.Cms	`< 13.14.0`	`13.14.0`
Umbraco.Cms	`>= 17.3.0-rc, < 17.4.0`	`17.4.0`

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

Umbraco.Cms NuGet → `13.14.0`

dotnet

dotnet add package Umbraco.Cms --version 13.14.0

Severity breakdown

CVSS 3.1 5.4

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: Required
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: None

Weakness

CWE-601: URL Redirection to Untrusted Site ('Open Redirect')

The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.

How to prevent it

Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright. Use a list of approved URLs or domains to be used for redirection.
Architecture and Design: Use an intermediate disclaimer page that provides the user with a clear warning that they are leaving the current site. Implement a long timeout before the redirect occurs, or force the user to click on the link. Be careful to avoid XSS problems (CWE-79) when generating the disclaimer page.
Architecture and Design: When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs. For example, ID 1 could map to "/login.asp" and ID 2 could map to "http://www.example.com/". Features such as the ESAPI AccessReferenceMap [REF-45] provide this capability.
Architecture and Design: Ensure that no externally-supplied requests are honored by requiring that all redirect requests include a unique nonce generated by the application [REF-483]. Be sure that the nonce is not predictable (CWE-330).
Architecture and Design, Implementation: Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls. Many open redirect problems occur because the programmer assumed that certain inputs could not be modified, such as cookies and hidden form fields.
Operation: Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].

References

Advisories

nvd.nist.gov/vuln/detail/CVE-2026-46616

Packages

github.com/umbraco/Umbraco-CMS

Timeline

May 21, 2026 Published
Oct 26, 2026 Last updated by the source
Oct 31, 2026 Latest EPSS score

Advisory	Severity	Why it's related
GHSA-wr57-hqmp-fgvh Umbraco: Delivery API leaks protected (Public Access) content through Content Picker / Multi-Node Tree Picker expansion	High	Also affects Umbraco.Cms
GHSA-vr9v-27gg-qgx4 Umbraco.Cms: XSS/HTML Injection in Umbraco Backoffice confirmation dialog	Medium	Also affects Umbraco.Cms
GHSA-rhcg-3h8r-v6vp Umbraco Affected by Vertical Privilege Escalation via Missing Authorization Checks	High	Also affects Umbraco.Cms
GHSA-vrqc-59mw-qqg7 Umbraco has Stored XSS in UFM Rendering Pipeline via Permissive DOMPurify Attribute Filtering	Medium	Also affects Umbraco.Cms
GHSA-fpvf-fvp5-996r Umbraco Backoffice API Allows Unauthorized Modification of Domain Data	Medium	Also affects Umbraco.Cms
GHSA-54mj-vcvj-q3v5 Umbraco CMS has an arbitrary file upload vulnerability	Critical	Also affects Umbraco.Cms
GHSA-hfv2-pf68-m33x Umbraco Vulnerable to Improper File Access and Credential Exposure in Dictionary Import Functionality	Medium	Also affects Umbraco.Cms
GHSA-pgvc-6h2p-q4f6 Umbraco CMS disclosure of configured password requirements	Medium	Also affects Umbraco.Cms

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