# CVE-2026-126563: Semantic MediaWiki reflected XSS in TimeValueFormatter

Source: https://junglewise.ai/threats/cve-2026-126563-semantic-mediawiki-2-4-0-before-7-4-1-contains-a-reflected-cross  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-11. Updated: 2026-11-11  
License: CC BY 4.0 with a link back

CVE-2026-126563 · Severity: medium · CVSS 6.1 · Published 2026-11-11

Semantic MediaWiki is a knowledge management extension for MediaWiki that allows structured data queries. An unauthenticated attacker can craft a malicious URL containing HTML markup in a date format parameter, which will be reflected and executed in the browser of a logged-in wiki user without proper escaping, leading to session hijacking or account compromise.

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

## Quick answers

**Is CVE-2026-126563 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-126563 being exploited in the wild.

**How severe is CVE-2026-126563?** Medium severity, with a CVSS score of 6.1, published 11 November 2026.

**Which products and versions are affected?** SemanticMediaWiki Semantic MediaWiki 2.4.0 before 7.4.1.

**Is there a fix for CVE-2026-126563?** Yes: fixed in 7.4.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-126563 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-126563?** Check whether you run SemanticMediaWiki 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 7.4.1

## Technical details

A reflected cross-site scripting vulnerability exists in the TimeValueFormatter::getCaptionFromFreeFormat() method, which emits free-format date captions in HTML output without escaping user-supplied format strings. Attackers craft Special:Ask URLs with HTML markup in the date printout format parameter (#-F[...]) to inject script that executes in the victim's authenticated browser session. The vulnerability is fixed by escaping the caption when rendered as HTML while preserving raw output for non-HTML formats.

## Affected products

- SemanticMediaWiki Semantic MediaWiki 2.4.0 before 7.4.1

## Timeline

- 2026-11-11: disclosed

## References

- [https://github.com/SemanticMediaWiki/SemanticMediaWiki/blob/7.4.0/src/DataValues/ValueFormatters/TimeValueFormatter.php](https://github.com/SemanticMediaWiki/SemanticMediaWiki/blob/7.4.0/src/DataValues/ValueFormatters/TimeValueFormatter.php)
- [https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/01cb81a6da7af743d2a5eb334db10e52b7318c56](https://github.com/SemanticMediaWiki/SemanticMediaWiki/commit/01cb81a6da7af743d2a5eb334db10e52b7318c56)

## Related threats

- [Semantic MediaWiki stored XSS in Special:Ask with ElasticStore](https://junglewise.ai/threats/cve-2026-126567-semantic-mediawiki-3-0-0-before-7-4-1-contains-a-stored-cross)
- [Semantic MediaWiki missing authorization in smwtask API](https://junglewise.ai/threats/cve-2026-116890-semantic-mediawiki-from-3-0-0-before-7-3-0-contains-a-missing)
- [Semantic MediaWiki uncontrolled recursion in query parser](https://junglewise.ai/threats/cve-2026-116871-semantic-mediawiki-3-0-0-before-7-3-1-contains-an-uncontrolled)