Apache Wicket: Improper Encoding or Escaping of Output (CVE-2026-83559)
Published Last modified Sources: CVE.org
What is affected, what to do
Improper encoding or escaping of output in Apache Wicket. org.apache.wicket.core.util.string.JavaScriptUtils#escapeQuotes() replaces each single quote in its input with a backslash and a single quote, and each double quote with a backslash and a double quote, so that the value can be placed inside a JavaScript string literal. It does not escape the backslash, which is the character that has to be escaped, and escaped first, for the rest of that escaping to hold.
The available sources name no fixed version. Check the vendor guidance in the references below.
- Affected
- Apache Wicket
lte 8.0.0..8.19.0 - Apache Wicket
lte 9.0.0..9.24.0 - Apache Wicket
lte 10.0.0..10.11.0
- Apache Wicket
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Metrics
7.4
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: Vendor (CNA), CVSS v4
7.4
CVSS v4
Severity High on the scale from 0 to 10.
Source: CVE.org
—
EPSS score
No value is available for this vulnerability.
Show all metrics
- Severity
- High
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 67.00 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 7.4 Methodology
CVSS v4
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 7.4
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-116
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
Improper encoding or escaping of output in Apache Wicket. org.apache.wicket.core.util.string.JavaScriptUtils#escapeQuotes() replaces each single quote in its input with a backslash and a single quote, and each double quote with a backslash and a double quote, so that the value can be placed inside a JavaScript string literal. It does not escape the backslash, which is the character that has to be escaped, and escaped first, for the rest of that escaping to hold. A value that already holds a backslash immediately before a quote therefore ends up with two backslashes in front of that quote: the first escapes the second, the quote itself is left unescaped, and it closes the literal. Whatever the value carries after that point is no longer text but JavaScript, and it runs in the application's origin and in the session of the user looking at the page. The method is public, is not deprecated, and its documentation states that its result can be part of a JavaScript call such as an alert; the only limitation it notes concerns JSON values, which need different escaping. An application is affected wherever it calls the method itself and places the result inside a JavaScript string literal, from its own code or from a component of its own or of a third party, and the value it escapes holds data an attacker can influence. There is no further condition, and no component of Wicket has to be involved: the application is using the method for what its documentation offers, and the method does not deliver it. Two components shipped with Wicket Extensions pass a value through the method. org.apache.wicket.extensions.ajax.markup.html.AjaxEditableLabel writes the editor's first error feedback message into a single-quoted JavaScript string literal in the Ajax response, so an application is affected through that component where the message shown for a failed edit holds data an attacker can influence, whether that is the submitted value itself or another variable the application sets on the validation error. A validation message can carry the submitted value, because input is a message variable that every form component supplies for its own validation errors, and the documentation shows overriding a validator's message to include it; none of the message bundles shipped with Wicket interpolates it, so an application that has not written such a message is not affected through this component. org.apache.wicket.extensions.ajax.markup.html.repeater.AjaxListPanel passes the serialized markup tag of an appended component through the method and is not affected: the tag comes from the panel's own markup file, and a quote in any of its attribute values, the component's markup id included, is written as a character reference by the tag serialization and cannot close the literal. 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.
Source: cvelistv5, NVD (NIST)
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| Apache Software Foundation | Apache Wicket |
|
|
Vendors and products
Weakness classes (CWE)
CWE-116Improper Encoding or Escaping of Output
Class
The product prepares a structured message for communication with another component, but encoding or escaping of the data is either missing or done incorrectly. As a result, the intended structure of the message is not preserved.
Entry at MITRE CWE-116
References & sources
- lists.apache.orgthread.html/77kc85ztkxdpp7wg7cv61c4539j9s1g3Vendor advisory
Changes to this CVE
Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).
ReceivedApache
CVSS V4.0: AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Weakness type: CWE-116
Description added or changed
Show 5 original changes
Individual changes of this event as published by NVD Type Action Before After Description added —Improper encoding or escaping of output in Apache Wicket. org.apache.wicket.core.util.string.JavaScriptUtils#escapeQuotes() replaces each single quote in its input with a backslash and a single quote, and each double quote with a backslash and a double quote, so that the value can be placed inside a JavaScript string literal. It does not escape the backslash, which is the character that has to be escaped, and escaped first, for the rest of that escaping to hold. A value that already holds a backslash immediately before a quote therefore ends up with two backslashes in front of that quote: the first escapes the second, the quote itself is left unescaped, and it closes the literal. Whatever the value carries after that point is no longer text but JavaScript, and it runs in the application's origin and in the session of the user looking at the page. The method is public, is not deprecated, and its documentation states that its result can be part of a JavaScript call such as an alert; the only limitation it notes concerns JSON values, which need different escaping. An application is affected wherever it calls the method itself and places the result inside a JavaScript string literal, from its own code or from a component of its own or of a third party, and the value it escapes holds data an attacker can influence. There is no further condition, and no component of Wicket has to be involved: the application is using the method for what its documentation offers, and the method does not deliver it. Two components shipped with Wicket Extensions pass a value through the method. org.apache.wicket.extensions.ajax.markup.html.AjaxEditableLabel writes the editor's first error feedback message into a single-quoted JavaScript string literal in the Ajax response, so an application is affected through that component where the message shown for a failed edit holds data an attacker can influence, whether that is the submitted value itself or another variable the application sets on the validation error. A validation message can carry the submitted value, because input is a message variable that every form component supplies for its own validation errors, and the documentation shows overriding a validator's message to include it; none of the message bundles shipped with Wicket interpolates it, so an application that has not written such a message is not affected through this component. org.apache.wicket.extensions.ajax.markup.html.repeater.AjaxListPanel passes the serialized markup tag of an appended component through the method and is not affected: the tag comes from the panel's own markup file, and a quote in any of its attribute values, the component's markup id included, is written as a character reference by the tag serialization and cannot close the literal. 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.CVSS added —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:XWeakness type (CWE) added —CWE-116Affected versions (publisher) added —New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/83xxx/CVE-2026-83559.json">CVE-2026-83559</a>Reference added —https://lists.apache.org/thread.html/77kc85ztkxdpp7wg7cv61c4539j9s1g3Source identifier: security@apache.org
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