---
id: "CVE-2026-116883"
kind: "vulnerability"
aliases: ["CVE-2026-116883"]
title: "Semantic MediaWiki: schema descriptions allow stored cross-site scripting by editors"
severity: "medium"
cvss: 4.8
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["mediawiki", "package", "self-hosted", "semantic-mediawiki"]
not_affected_if: ["no-schema-editors", "version-7.3.1-or-later"]
published_at: "2026-10-27T11:17:30+00:00"
first_seen_at: "2026-10-27T11:31:27+00:00"
updated_at: "2026-10-27T11:32:15+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-116883", "first_seen_at": "2026-10-27T11:31:27+00:00"}]
---

# Semantic MediaWiki: schema descriptions allow stored cross-site scripting by editors

Semantic MediaWiki versions from 3.1.0 before 7.3.1 do not escape schema descriptions, so HTML saved by a user with the smw-schemaedit permission is rendered as-is. Other users who view the schema can have script run in their browser, and the page content can be altered.

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

## How to check

- Check the installed Semantic MediaWiki version in Special:Version or in the extension's composer.lock or extension.json.
- Check whether any users hold the `smw-schemaedit` permission (unknown how to list them from the sources).

## Fix

- Upgrade Semantic MediaWiki to `7.3.1` or later.

## Timeline

- 2026-10-27T11:31:27+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-116883

## From the sources

Semantic MediaWiki from 3.1.0 before 7.3.1 contains a stored cross-site scripting vulnerability that allows authenticated schema editors to inject HTML through schema descriptions. Attackers with the smw-schemaedit permission can save HTML that is passed unescaped to Html::rawElement() in HtmlBuilder, altering pages and targeting users who view the schema.

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