---
id: "CVE-2026-103863"
kind: "vulnerability"
aliases: ["CVE-2026-103863"]
title: "Apache Sling Engine: included components bypass protections, enabling stored XSS"
severity: "unknown"
cvss: null
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["apache-sling", "cms", "java", "package", "stored-xss"]
not_affected_if: ["patched-version"]
published_at: "2026-11-05T13:17:06+00:00"
first_seen_at: "2026-11-05T13:39:08+00:00"
updated_at: "2026-11-05T13:40:10+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-103863", "first_seen_at": "2026-11-05T13:39:08+00:00"}]
exploit_sources: []
---

# Apache Sling Engine: included components bypass protections, enabling stored XSS

Apache Sling Engine lets an included component change Content-Type, charset and redirect settings in ways that skip its header and content-type checks. An attacker can therefore store script in a page that runs in other users' browsers despite the protections being enabled.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the Apache Sling Engine version in your bundle or pom.xml (for example `org.apache.sling.engine`).

## Fix

- Apache Sling Engine: upgrade to `3.0.4` or later.

## Timeline

- 2026-11-05T13:39:08+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-103863

## From the sources

Improper neutralization of input during web page generation ('cross-site scripting') vulnerability in Apache Sling Engine. Content-Type, charset, and redirect changes from an included component evade the  protectheaders / checkcontenttype  enforcement through setHeader(), repeated calls to setContentType(), the charset APIs, Servlet 6.1 redirect overloads, and stale config - enabling stored XSS despite enabled protections.



This issue affects Apache Sling Engine before 3.0.4.



Users are recommended to upgrade to version 3.0.4, which fixes the issue.

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