---
id: CVE-2026-120421
title: Reflected XSS via client window id in URL client window mode
summary: >-
  In Eclipse Mojarra versions 2.2.0 through 4.0.28, 4.1.0 through 4.1.19, and
  5.0.0-M1 through 5.0.0-M11, when URL client window mode is enabled
  (`jakarta.faces.CLIENT_WINDOW_MODE=url`), the client window id from the
  `jfwid` or `jakarta.fa…
severity: medium
cvss: 6.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'
cvssSource: cna
cwe:
  - CWE-79
vendor: Eclipse Foundation
product: Eclipse Mojarra
affected:
  - eclipse_mojarra >= 2.2.0 < 4.0.29
  - eclipse_mojarra >= 4.1.0 < 4.1.20
  - eclipse_mojarra >= 5.0.0-M1 < 5.0.0-M12
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-04T18:18:42.408189Z'
published: '2026-11-04'
updated: '2026-11-04'
sourceUpdated: '2026-11-04T20:00:57.838Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-120421'
references:
  - url: 'https://gitlab.eclipse.org/security/cve-assignment/-/work_items/536'
  - url: >-
      https://gitlab.eclipse.org/security/vulnerability-reports/-/work_items/1332
tags:
  - cve.org
ingestedAt: '2026-11-05T21:36:00.524Z'
epss: 0.0021
epssPercentile: 0.1128
---

## Overview

In Eclipse Mojarra versions 2.2.0 through 4.0.28, 4.1.0 through 4.1.19, and 5.0.0-M1 through 5.0.0-M11, when URL client window mode is enabled (`jakarta.faces.CLIENT_WINDOW_MODE=url`), the client window id from the `jfwid` or `jakarta.faces.ClientWindow` request parameter is appended to generated URLs without URL-encoding. `h:button` renders such a URL into a JavaScript string literal, which allows reflected cross-site scripting. With `com.sun.faces.enableCspNonce=true`, the injected script runs on page load inside the nonce script element, bypassing the Content Security Policy.

## Affected

- `eclipse_mojarra >= 2.2.0 < 4.0.29`
- `eclipse_mojarra >= 4.1.0 < 4.1.20`
- `eclipse_mojarra >= 5.0.0-M1 < 5.0.0-M12`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.