Apache Wicket: Improper Neutralization of Input During Web Page Generation
CVE-2026-82956 is a high-severity improper neutralization of input during web page generation vulnerability in Apache Wicket from Apache, with a CVSS 4.0 base score of 7.6 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected Apache Wicket versions: 8.0.0 through 8.19.0; 9.0.0 through 9.24.0; 10.0.0 through 10.11.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.3% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Apache Wicket you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache Wicket | 8.0.0 through 8.19.0; 9.0.0 through 9.24.0; 10.0.0 through 10.11.0 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Attack requirements
- PresentThe target must be in a specific state or configuration for the attack to work.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- PassiveA user only needs to do something routine, such as viewing a page.
- Confidentiality (vulnerable system)
- HighSerious loss of confidentiality on the vulnerable system.
- Integrity (vulnerable system)
- HighSerious loss of integrity on the vulnerable system.
- Availability (vulnerable system)
- NoneNo loss of availability on the vulnerable system.
- Confidentiality (other systems)
- NoneNo loss of confidentiality on systems beyond the vulnerable one.
- Integrity (other systems)
- NoneNo loss of integrity on systems beyond the vulnerable one.
- Availability (other systems)
- NoneNo loss of availability on systems beyond the vulnerable one.
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/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. Scored by CNA (apache.org).
Official description
Improper neutralization of input during web page generation in Apache Wicket. org.apache.wicket.ajax.AjaxNewWindowNotifyingBehavior notices that a page instance has been opened in a second browser window or tab. It asks the browser for the value of window.name, which reaches the server as the request parameter windowName, and remembers what the browser reported in a field of the behaviour. That field is part of the page's serialized state, so the remembered value stays in the page store for as long as the page instance does. On every later render of that page instance the behaviour builds the precondition of its Ajax call by substituting the remembered value into a single-quoted JavaScript string literal, and Wicket writes that precondition into the page as raw JavaScript, because the precondition of an Ajax call listener is script supplied by the caller and is emitted without quoting or escaping. Nothing on that path escapes the value. The window name is client-supplied and Wicket applies no validation to it, so a remembered name containing a single quote ends the literal and the rest of it runs as script in the application's origin, every time that page instance is rendered. An application is affected only where it has explicitly added AjaxNewWindowNotifyingBehavior to a component. No part of the framework installs the behaviour, so an application that does not use it is not affected. The name the behaviour generates for itself, when the browser reports no name at all, is a random UUID and is not client-supplied. 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 are recommended to upgrade to version 8.20.0, 9.25.0 or 10.12.0, which fix the issue.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Input During Web Page Generation
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.
How developers prevent this class of flaw
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. Examples of libraries and frameworks that make it easier to generate properly encoded output include Microsoft's Anti-XSS library, the OWASP ESAPI Encoding module, and Apache Wicket.
- Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
More Improper Neutralization of Input During Web Page Generation vulnerabilities (CWE-79)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in Apache Wicket
- 7.6 High severity
- 7.4 High severity
- 8.3 High severity
- 8.3 High severity
- 7.4 High severity
- 7.4 High severity
Recent Improper Neutralization of Input During Web Page Generation vulnerabilities
- 7.6 High severity
- 7.1 High severity
- 8.0 High severity
- 7.2 High severity
- 7.2 High severity
- 7.2 High severity
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