# CVE-2026-116886: Semantic MediaWiki stored cross-site scripting in External identifier values

Source: https://junglewise.ai/threats/cve-2026-116886-semantic-mediawiki-from-2-5-0-before-7-3-1-contains-a-stored  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-27. Updated: 2026-10-27  
License: CC BY 4.0 with a link back

CVE-2026-116886 · Severity: medium · CVSS 5.4 · Published 2026-10-27

Semantic MediaWiki is an extension that adds semantic data management to MediaWiki wikis. A stored cross-site scripting vulnerability allows users with page-editing rights to inject malicious scripts through External identifier property values, which are rendered unescaped on the Special:Browse page. When an administrator or other user views the affected page, the attacker's script executes in their browser session, potentially allowing the attacker to steal session tokens or perform unauthorized actions with the victim's privileges.

Technologies: [Semantic MediaWiki](https://junglewise.ai/threats/technologies/semantic-mediawiki). Vendors: [Semantic MediaWiki](https://junglewise.ai/threats/vendors/semantic-mediawiki).

## Quick answers

**Is CVE-2026-116886 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-116886 being exploited in the wild.

**How severe is CVE-2026-116886?** Medium severity, with a CVSS score of 5.4, published 27 October 2026.

**Which products and versions are affected?** Semantic MediaWiki 2.5.0 to before 7.3.1.

**Is there a fix for CVE-2026-116886?** Yes: fixed in 7.3.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-116886 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-116886?** Check whether you run Semantic MediaWiki at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 7.3.1

## Technical details

The vulnerability exists in the ExternalIdentifierValue class (src/DataValues/ExternalIdentifierValue.php), which overrides the getShortHTMLText method and returns user-controlled captions without HTML escaping. The issue is in three branches: when no formatter URI is configured, the raw caption is returned; when a formatter URI is set, the caption is placed unescaped as the body of an anchor element. The vulnerable value is then rendered through an unescaped Mustache template in Special:Browse with no sanitization. An attacker with page-edit rights can store a payload via External identifier property annotation that executes JavaScript in any viewer's session.

## Affected products

- Semantic MediaWiki Semantic MediaWiki 2.5.0 to before 7.3.1

## Timeline

- 2026-09-28: disclosed
- 2026-10-27: advisory

## References

- [https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-2gfw-3hj2-wfq5](https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-2gfw-3hj2-wfq5)
- [https://www.vulncheck.com/advisories/semantic-mediawiki-before-7.3.1-stored-xss-via-external-identifier-in-special-browse](https://www.vulncheck.com/advisories/semantic-mediawiki-before-7.3.1-stored-xss-via-external-identifier-in-special-browse)

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- [Semantic MediaWiki authorization bypass in edit protection](https://junglewise.ai/threats/cve-2026-126566-semantic-mediawiki-7-3-1-before-7-4-1-contains-an-incorrect)
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- [Semantic MediaWiki missing authorization in page edit protection](https://junglewise.ai/threats/cve-2026-126561-semantic-mediawiki-2-5-0-before-7-4-1-contains-a-missing)