---
id: "CVE-2026-126563"
page: "https://infrastack.ai/live/CVE-2026-126563"
kind: "vulnerability"
aliases: ["CVE-2026-126563"]
title: "Semantic MediaWiki: crafted Special:Ask URL runs script in victim's browser"
severity: "medium"
cvss: 6.1
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["mediawiki", "package", "self-hosted", "semantic-mediawiki"]
not_affected_if: ["version-7.4.1-or-later"]
published_at: "2026-11-11T03:16:50+00:00"
first_seen_at: "2026-11-11T03:25:00+00:00"
updated_at: "2026-11-11T03:26:27+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-126563", "first_seen_at": "2026-11-11T03:25:00+00:00"}]
exploit_sources: []
---

# Semantic MediaWiki: crafted Special:Ask URL runs script in victim's browser

Link for people: https://infrastack.ai/live/CVE-2026-126563 (this .md is for agents)

Semantic MediaWiki 2.4.0 before 7.4.1 emits free-format date captions as HTML without escaping them. An attacker can craft a Special:Ask URL with HTML in a date printout format so that script runs in a logged-in victim's browser session.

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

## How to check

- Check the installed Semantic MediaWiki version in the wiki's Special:Version page or the extension's composer.json, and see whether it is between `2.4.0` and `7.4.1`.

## Fix

- Semantic MediaWiki: upgrade to `7.4.1` or later.

## Timeline

- 2026-11-11T03:25:00+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-126563

## Documents

- [advisory] Vendor advisory: github.com https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-h252-mj7p-58q7
- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/semantic-mediawiki-2.4.0-before-7.4.1-reflected-xss-via-special-ask-date-format
- [fix] Patch: github.com https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/01cb81a6da7af743d2a5eb334db10e52b7318c56
- [fix] Release notes: github.com https://github.com/SemanticMediaWiki/SemanticMediaWiki/releases/tag/7.4.1

## From the sources

Semantic MediaWiki 2.4.0 before 7.4.1 contains a reflected cross-site scripting vulnerability in TimeValueFormatter::getCaptionFromFreeFormat(), which emits free-format date captions in HTML without escaping. Unauthenticated attackers can craft a Special:Ask URL with HTML markup in a date printout format (#-F[...]) to execute script in a logged-in victim's browser session.

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_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_