Semantic MediaWiki affected by reflected XSS in `Special:Ask` via a forged cursor pagination token

Summary

Semantic MediaWiki is a free, open-source extension to MediaWiki that lets users store and query data within the wiki's pages. In versions 7.0.0 through 7.1.0, `Special:Ask` accepts a `cursor` query parameter for keyset pagination (added in 7.0.0). The token is decoded by `CursorEncoder`, which is an unsigned base64url-encoded JSON blob, so its contents are fully attacker-controlled. When the cursor's sort anchor does not match the request's `sort=` / `order=`, `QueryCreator::applyCursorIfRequested()` builds an error message by interpolating the attacker-controlled `sort_prop` / `sort_order` values into a raw string via `Query::addErrors()`. Unlike SMW's message-key errors, this raw string bypasses the message layer's sanitization (`ProcessingErrorMsgHandler::normalizeAndDecodeMessages()` passes a non-key, non-encoded string through unchanged). `ErrorWidget::queryError()` then assembles the errors and passes them to `Html::errorBox()`, whose first argument is emitted as raw HTML. The result is a reflected cross-site scripting vulnerability: a crafted `cursor` token containing markup in `sort_prop` (or `sort_order`) executes script in the victim's browser on the wiki origin. No authentication or special permission is required. The payload is delivered via a crafted link. Version 7.2.0 contains a fix.

Timeline

1. Sep 18, 2026, 4:58 PM UTCCVE published
2. Sep 18, 2026, 5:22 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Sep 18, 2026, 5:22 PM UTCRecord last updated

Affected versions

• SemanticMediaWiki SemanticMediaWiki

  From 7.0.0 · fixed in 7.2.0

• mediawiki/semantic-media-wikiPackagist

  From 7.0.0 · fixed in 7.2.0

References 2