CVE-2026-84231 XSS en ExternalLink de Apache Wicket con etiquetas que no son ancla
ExternalLink genera un manejador onclick en JavaScript cuando la etiqueta del componente no es a, link ni area, y concatena la URL del modelo en un literal entre comillas simples sin escaparla para ese contexto; lo mismo ocurre con PopupSettings#getPopupJavaScript(). El escapado de markup convierte la apóstrofe en referencia de carácter, que el navegador decodifica, permitiendo ejecutar script en el origen de la aplicación.
CVSS 4.0
- Probabilidad de explotación · EPSS del 09/110,3 % · percentil 26
- Explotada activamenteNo confirmada
- Exploit públicoNo conocido
Afectados
Apache Software Foundation Apache Wicket
desde 8.0.0 hasta 8.19.0
Qué hacer
- Verificá si usás Apache Wicket y en qué versión.
- Actualizá a la versión corregida que indique el fabricante en su aviso o aplicá su mitigación.
- Revisá registros y accesos de los sistemas expuestos para descartar un uso previo.
Calculadora CVSS
CVSS 4.0 · 7.4 ALTA
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- Vector de ataqueRed
- Complejidad del ataqueBaja
- Requisitos del ataquePresentes
- Privilegios requeridosNinguno
- Interacción del usuarioActiva
- Confidencialidad (sistema vulnerable)Alta
- Integridad (sistema vulnerable)Alta
- Disponibilidad (sistema vulnerable)Ninguna
- Confidencialidad (sistemas posteriores)Ninguna
- Integridad (sistemas posteriores)Ninguna
- Disponibilidad (sistemas posteriores)Ninguna
Descripción original
Improper neutralization of input during web page generation in Apache Wicket.
org.apache.wicket.markup.html.link.ExternalLink builds a JavaScript click handler and writes it into the tag's onclick attribute whenever the markup tag the component is bound to is not an a, link or area element. The URL held in the component's model is concatenated into a single-quoted JavaScript string literal in that handler without being escaped for that context. The same happens on the neighbouring branch, taken when popup settings are attached, where the value is concatenated into the window.open() call built by org.apache.wicket.markup.html.link.PopupSettings#getPopupJavaScript(). The only escaping applied is the markup escaping that every attribute value receives as the tag is written, which replaces an apostrophe with a character reference. A browser decodes character references in an attribute value before it compiles the event handler, so the apostrophe is restored, closes the string literal, and the rest of the model value is executed as script in the application's origin.
An application is affected where it binds an ExternalLink to a markup tag that is not an anchor, such as a button or a span, and the URL in the model holds data an attacker can influence, which is the ordinary use of the component rather than a misuse of it. Nothing runs until a user activates the element.
This issue affects Apache Wicket: from 8.0.0 through 8.19.0. Users of Apache Wicket 7.x or older, which are no longer supported, should upgrade to a supported version.
Users are recommended to upgrade to version 8.20.0, which fixes the issue.
Referencias (1)
Resumen traducido automáticamente de la descripción original. Fuente: Nureq Monitor. Cómo funciona.