CVE-2026-82558 in Wicket
Summary
by MITRE • 11/02/2026
Missing authorization in Apache Wicket.
org.apache.wicket.protocol.ws.api.WebSocketBehavior, through which Wicket's native WebSocket support hands a message sent by the client to the application, calls its onMessage() callbacks without checking whether the client may invoke the component the behavior is attached to. Wicket opens a single WebSocket connection per page, and a message received on it is delivered to every WebSocketBehavior of that page. For an Ajax behavior Wicket makes this check before invoking it, through Behavior#canCallListener(Component), which refuses a component that is not visible or not enabled, including one for which the IAuthorizationStrategy denies the RENDER or ENABLE action. A WebSocketBehavior attached to such a component, or to a child of one, therefore receives the client's text and binary messages, together with a WebSocketRequestHandler that writes back to that client, where an Ajax behavior on the same component would be refused.
An application is affected where it attaches a WebSocketBehavior that overrides onMessage() to a component that it hides, disables, or restricts through its IAuthorizationStrategy, for example with MetaDataRoleAuthorizationStrategy or the AuthorizeAction annotation. The client needs a session of their own and a page of their own that contains such a component: messages are delivered only to pages in the page store of the client's own session, so this gives no access to another user's session, page or connection. Messages pushed by the server are not affected.
This issue affects Apache Wicket: from 8.0.0 through 8.19.0, from 9.0.0 through 9.24.0, from 10.0.0 through 10.11.0. Older, unsupported releases from 6.0.0 onwards are also affected. Users are recommended to upgrade to version 8.20.0, 9.25.0 or 10.12.0, which fix the issue.
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Analysis
by VulDB Data Team • 11/02/2026
The vulnerability identified in Apache Wicket represents a critical authorization bypass within its native WebSocket implementation, specifically affecting the org.apache.wicket.protocol.ws.api.WebSocketBehavior class. This flaw stems from an inconsistency in how access control checks are applied to different types of component behaviors. In standard Ajax interactions, Wicket employs a robust security mechanism via Behavior#canCallListener(Component) which validates whether a user is permitted to interact with a specific component by checking visibility, enabled status, and authorization strategy constraints such as RENDER or ENABLE actions. However, the WebSocket implementation fails to replicate this rigorous validation process when processing incoming messages from clients. Consequently, any client possessing an active session can send text or binary messages through a WebSocket connection attached to a page, triggering onMessage callbacks even if those components are explicitly hidden, disabled, or restricted by authorization policies like MetaDataRoleAuthorizationStrategy or AuthorizeAction annotations.
From a technical perspective, the root cause lies in the architectural design of Wicket's session and page management model. Apache Wicket maintains a single WebSocket connection per page instance within a user's session, ensuring that messages are delivered only to components on pages stored in that specific client's session context. This isolation prevents cross-session attacks where one user might attempt to manipulate another user's active sessions or access their private data directly through the socket layer. The vulnerability is strictly confined to the current authenticated session of the attacker, meaning it does not constitute a remote code execution vector against other users but rather allows an authorized user to bypass application-level business logic and security constraints intended for specific components within their own view state.
The operational impact of this flaw centers on unauthorized access to restricted functionality or data exposure that should have been prevented by server-side authorization checks. An attacker who has valid credentials can exploit the missing check in WebSocketBehavior to invoke actions or retrieve information from components that are supposed to be inaccessible due to role-based restrictions, visibility settings, or disabled states. This undermines the integrity of the application's security model, potentially leading to privilege escalation within the context of a single user account or exposure of sensitive business logic intended for administrative roles only. The ability to send binary and text messages means attackers can also attempt to inject malicious payloads if those components process such inputs without additional sanitization, although the primary issue remains the lack of authorization verification before callback invocation.
This vulnerability is classified under CWE-284 Improper Access Control as it involves a failure to enforce proper access control policies on a specific interface or method call. In terms of MITRE ATT&CK mapping, this behavior aligns with T1078 Valid Accounts and potentially T1531 Account Access Removal if the attacker uses the bypassed functionality to alter account states, though primarily it fits within unauthorized access patterns where legitimate credentials are used to perform actions outside their intended scope. The flaw affects multiple versions of Apache Wicket including releases from 6.0.0 through 8.19.0, 9.0.0 through 9.24.0, and 10.0.0 through 10.11.0, indicating a systemic issue in the WebSocket behavior implementation across several major release lines that persisted for an extended period due to the oversight of parity between Ajax and WebSocket security checks.
To mitigate this risk, organizations running affected versions must upgrade immediately to Apache Wicket version 8.20.0, 9.25.0, or 10.12.0 where the missing authorization check has been implemented in the WebSocketBehavior class. For applications unable to upgrade instantly, a temporary workaround involves ensuring that no WebSocketBehaviors are attached to components that rely on visibility, enabled status, or custom IAuthorizationStrategy restrictions for security purposes. Developers should audit their codebase for any WebSocket implementations and verify that all component interactions undergo equivalent validation logic as Ajax behaviors. Additionally, implementing defense-in-depth strategies such as input validation on message handlers and reviewing role-based access control configurations can help reduce the blast radius of this vulnerability until a permanent patch is applied.