---
id: "CVE-2026-116886"
kind: "vulnerability"
aliases: ["CVE-2026-116886"]
title: "Semantic MediaWiki: stored XSS via External identifier values runs scripts"
severity: "medium"
cvss: 5.4
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["mediawiki", "package", "self-hosted", "semantic-mediawiki"]
not_affected_if: ["already-on-7.3.1-or-later", "no-external-identifier-properties"]
published_at: "2026-10-27T11:17:30+00:00"
first_seen_at: "2026-10-27T11:31:27+00:00"
updated_at: "2026-10-27T11:32:11+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-116886", "first_seen_at": "2026-10-27T11:31:27+00:00"}]
---

# Semantic MediaWiki: stored XSS via External identifier values runs scripts

Semantic MediaWiki versions from 2.5.0 before 7.3.1 render External identifier property values unescaped on Special:Browse. A user with page-edit rights can store a script payload that runs in the browser of anyone who views the page, including administrators.

_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 the `composer.lock` / `extensions/SemanticMediaWiki` directory.
- Check whether any pages use the External identifier property type.

## 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-2026-116886

## From the sources

Semantic MediaWiki from 2.5.0 before 7.3.1 contains a stored cross-site scripting vulnerability that allows users with page-edit rights to inject scripts via External identifier property values. Attackers can annotate markup payloads that ExternalIdentifierValue renders unescaped on Special:Browse, executing JavaScript in viewers' sessions, including administrators.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_