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Response snapshot Nov 2, 2026, 02:36 UTC

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VulnerabilityCVE-2026-84231

Improper neutralization of input during web page generation in Apache Wicket.

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.

At a glance

Exploited
Not known
Severity
7.4 High (CVSS 4.0)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-84231 (opens a new tab)

What happened

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.

Continue reading

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.

Scores and how they were measured

CVSS base severity

7.4

Version 4.0As of

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Sources

  1. Primary source

    NVD CVE-2026-84231 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 1). Improper neutralization of input during web page generation in Apache Wicket. (CVE-2026-84231). https://kevwire.com/record/CVE-2026-84231

MLA

"Improper neutralization of input during web page generation in Apache Wicket. (CVE-2026-84231)." KEVWire, 1 Nov. 2026, kevwire.com/record/CVE-2026-84231.

Chicago

KEVWire. "Improper neutralization of input during web page generation in Apache Wicket. (CVE-2026-84231)." Last modified November 1, 2026. https://kevwire.com/record/CVE-2026-84231.

Evidence summary (plain text)

Improper neutralization of input during web page generation in Apache Wicket. (Nov 1, 2026).
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.
CVSS 7.4 (version 4.0; evidence as of Nov 1, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-84231).
Sources:
NVD CVE-2026-84231: https://nvd.nist.gov/vuln/detail/CVE-2026-84231
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-01T23:15:57.054Z&lastModEndDate=2026-11-02T00:50:55.984Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-01T22:40:59.243Z&lastModEndDate=2026-11-02T00:15:55.446Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-01T22:05:59.838Z&lastModEndDate=2026-11-01T23:40:56.426Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2026-84231.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 2, 2026, 00:50 UTC. Ingestion is not an independent editorial investigation.

NVD status: Received. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

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