CVE-2026-83594
HighCVSS 8.3Summary
A vulnerability in Apache Wicket affects the FileUploadToResourceField component, whose Ajax callback reads the filesInfo request parameter without binding it to an actual upload. The UploadInfo#get() method allocates a byte array based on the client-supplied size, allowing a single request to exhaust the JVM heap, while negative values trigger a NegativeArraySizeException.
Risk Assessment
An attacker able to load the page can repeatedly send small requests causing close to 2 GB heap allocation, leading to memory exhaustion and denial of service for all applications served by the Java virtual machine.
Recommendation
Upgrade Apache Wicket to version 9.25.0 or 10.12.0. If upgrading is not possible, consider denying the ENABLE action on the field via the authorization strategy or avoid calling UploadInfo#get().
Other vulnerabilities in Apache Wicket
See all- CVE-2026-95863High
Apache Wicket generates JavaScript that references rendered elements, placing markup ids and form input names inside single-quoted JavaScript string literals without proper escaping. A value containing a single quote or backslash can terminate the literal and inject script that runs in the application's origin when the page loads. The issue affects wicket-core and wicket-extensions in versions 8.0.0 through 8.19.0, 9.0.0 through 9.24.0, and 10.0.0 through 10.11.0.
- CVE-2026-87718Low
Apache Wicket 10.10.0, 10.11.0 and 9.24.0 do not set Content-Security-Policy headers on a page whose render request handler is wrapped in more than one IRequestHandlerDelegate. The framework unwraps only a single delegate level when deciding whether a request renders a page, so with a deeper chain, for example an application-provided delegating request mapper combined with CryptoMapper, the page is served without any CSP header even though CSP is enabled, and no error or warning is raised. The nonce-based protection Wicket applies to inline scripts and styles, together with any other CSP directives configured by the application, is thereby lost for those pages, exposing them to content injection the policy was meant to prevent. Applications on stock Wicket that do not wrap request handlers themselves are not affected. Versions before 10.10.0 and 9.24.0 handled nested delegates correctly.
- CVE-2026-84231High
A cross-site scripting (XSS) vulnerability in Apache Wicket arises from improper neutralization of input during web page generation. The ExternalLink component, when bound to a non-anchor element, concatenates the model URL into a JavaScript string literal in the onclick attribute without proper escaping, allowing script execution in the application's origin.
- CVE-2026-84177Medium
Apache Wicket has an incorrect behavior order: a file path is validated by PackageResourceGuard before the framework appends the style, variation and locale attributes. As a result, the file opened may differ from the file approved by the guard, allowing disclosure of HTML markup templates of components whose class names contain an underscore (e.g. Report_v2).
- CVE-2026-84172Medium
In Apache Wicket, PackageResourceGuard incorrectly allows component markup templates to be served as package resources when wicket-core is loaded by a class loader that cannot see the application's classes. In such a setup the check for a class file beside the template fails, and a request for the package resource URL returns the component's markup template with status 200. Disclosed content is developer-authored template material such as component structure, comments, inline script, and named endpoints.
- CVE-2026-84170High
A vulnerability in Apache Wicket affects AbstractFileUploadResource, the server side of the form-less upload offered by FileUploadToResourceField. The request size, single-part size and part-count limits are taken from request parameters (maxSize, fileMaxSize, fileCountMax) instead of application configuration, so a client can raise or omit them. The resource carries no authorization annotation, so by default requests need no authentication.
- CVE-2026-83559High
A vulnerability in Apache Wicket affects the JavaScriptUtils#escapeQuotes() method, which fails to escape the backslash character before quotes. A value containing a backslash immediately before a quote results in the quote being left unescaped, closing the JavaScript string literal and allowing JavaScript injection. The issue occurs when an application uses this method to place attacker-influenced data inside a JavaScript string literal, including via the AjaxEditableLabel component.
- CVE-2026-83539High
Cross-site scripting (XSS) vulnerability in the SmartLinkLabel and SmartLinkMultiLineLabel components of Apache Wicket. These components turn URLs found in text into hyperlinks and accept any URL scheme, including script-executing schemes such as javascript:. Escaping the model value does not help because the payload ends up in the href attribute rather than in element text.
- CVE-2026-82956High
A cross-site scripting (XSS) vulnerability in Apache Wicket affects the AjaxNewWindowNotifyingBehavior, which stores the client-supplied window.name value in the page's serialized state. That value is later substituted without escaping into a single-quoted JavaScript string literal in the Ajax call precondition, allowing arbitrary script execution in the application's origin on every render of the page instance. Only applications that explicitly add this behavior to a component are affected.
- CVE-2026-111089High
Apache Wicket writes texts from resource bundles (labels, CSS class names) into generated JavaScript and markup without context-appropriate escaping. A text containing a quote can terminate the literal or attribute and be parsed as script or markup in the application's origin. Affected components include MultiFileUploadField, Form, UploadProgressBar, FilterForm and TrapFocusBehavior in versions 8.0.0–8.19.0, 9.0.0–9.24.0 and 10.0.0–10.11.0.
Original NVD description (English source)
Memory allocation with an excessive size value in Apache Wicket. org.apache.wicket.markup.html.form.upload.resource.FileUploadToResourceField uploads files to a separately mounted resource rather than through a form, and is told the outcome afterwards over its own Ajax callback. That callback reads the request parameter filesInfo, a JSON array carrying a client file name, a size and a content type for each file, and turns it into the list of FileUploadToResourceField.UploadInfo that onUploadSuccess() receives. Nothing binds that JSON to an upload the resource performed and nothing re-derives it from the stored files, so the number of entries and every value in them are whatever the request supplied. The callback URL is rendered into the page, no prior upload is required, and both GET and POST reach it, so any client that can load the page can have the component report files that were never uploaded, without authenticating beyond whatever the page itself requires and without any user interaction. UploadInfo#get(), which the class offers as the way to obtain the bytes of an upload, allocates a byte array from UploadInfo#getSize() before it opens the file. The array is therefore sized by the number the request supplied, and the allocation happens even for a file that was never stored. One small request can cost the server close to two gigabytes of heap, and the request is trivially repeatable, so a few of them exhaust the heap for every request the Java virtual machine is serving. A size that the conversion to int turns negative instead throws NegativeArraySizeException, which the exception handler inside that method does not cover, so it escapes into the application. An application is affected where it uses FileUploadToResourceField, which is not the ordinary upload path through FileUploadField and Form and has to be extended and mounted deliberately. The allocation additionally requires the application to call UploadInfo#get() rather than reading UploadInfo#getFile() itself. Where the application denies the ENABLE action on the field through its authorization strategy, the callback is refused like any other listener. The 8.x line does not contain this component and is not affected. This issue affects Apache Wicket: from 9.14.0 through 9.24.0, from 10.0.0 through 10.11.0. Users are recommended to upgrade to version 9.25.0 or 10.12.0, which fix the issue.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS