Apache Wicket up to 8.19.0/9.24.0/10.11.0 SmartLinkLabel Strings.java cross site scripting

Summaryinfo

A vulnerability identified as problematic has been detected in Apache Wicket up to 8.19.0/9.24.0/10.11.0. Affected by this issue is the function org.apache.wicket.util.string.Strings.escapeMarkup of the file org/apache/wicket/util/string/Strings.java of the component SmartLinkLabel. The manipulation leads to cross site scripting. This vulnerability is listed as CVE-2026-83539. The attack may be initiated remotely. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Apache Wicket up to 8.19.0/9.24.0/10.11.0 and classified as problematic. This issue affects the function org.apache.wicket.util.string.Strings.escapeMarkup of the file org/apache/wicket/util/string/Strings.java of the component SmartLinkLabel. The manipulation with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. The summary by CVE is:

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.

It is possible to read the advisory at lists.apache.org. The identification of this vulnerability is CVE-2026-83539 since 08/31/2026. The exploitation is known to be easy. The attack may be initiated remotely. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 11/01/2026). The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

Upgrading to version 8.20.0, 9.25.0 or 10.12.0 eliminates this vulnerability.

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Productinfo

Vendor

• Apache

Name

• Wicket

Version

• 8.0
• 8.1
• 8.2
• 8.3
• 8.4
• 8.5
• 8.6
• 8.7
• 8.8
• 8.9
• 8.10
• 8.11
• 8.12
• 8.13
• 8.14
• 8.15
• 8.16
• 8.17
• 8.18
• 8.19.0
• 9.0
• 9.1
• 9.2
• 9.3
• 9.4
• 9.5
• 9.6
• 9.7
• 9.8
• 9.9
• 9.10
• 9.11
• 9.12
• 9.13
• 9.14
• 9.15
• 9.16
• 9.17
• 9.18
• 9.19
• 9.20
• 9.21
• 9.22
• 9.23
• 9.24.0
• 10.0
• 10.1
• 10.2
• 10.3
• 10.4
• 10.5
• 10.6
• 10.7
• 10.8
• 10.9
• 10.10
• 10.11.0

License

• open-source

Website

• Vendor: https://www.apache.org/

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