Semantic MediaWiki is a free, open-source extension to MediaWiki that lets users store and query data within the wiki's pages. Prior to version 7.2.0, query debug output (`format=debug`, or the `debug` request parameter on `Special:Ask`) is assembled by `SMW\Query\DebugFormatter` and emitted as raw HTML. Several of its sinks apply no output-context encoding, so attacker-controlled query input is reflected into the page without escaping. On `Special:Ask` the resulting string is concatenated into the page and sent through `OutputPage::addHTML`, never through the MediaWiki parser or Sanitizer. No special user right is required; an anonymous request suffices. This is a reflected XSS: the payload is taken from the request and echoed in the same response. Exploitation requires the query condition to target a text/blob-typed property (whose value is re-serialized verbatim); the predefined `_txt` properties (`Text`, etc.) that ship on every install satisfy this, so no attacker-created content is needed. Version 7.2.0 patches the issue.

Affected: Packagist: mediawiki/semantic-media-wiki

## Query debug output XSS

#### Failure mode

Semantic MediaWiki's query debug output (`format=debug`, or the `debug` request parameter on `Special:Ask`) is assembled by `SMW\Query\DebugFormatter` and emitted as raw HTML. Several of its sinks apply no output-context encoding, so attacker-controlled query input is reflected into the page without escaping:

- `buildHTML()` echoes the re-serialized ASK query string escaping only `[`; `<`, `>`, `"`, `'` pass through. - `prettifySQL()` returns the generated SQL verbatim. Query value literals are inlined into the SQL through the database layer's quoting (SQL-escaping only, no HTML encoding), so markup in a value survives. - `prettifyExplain()` echoes `EXPLAIN` output; on PostgreSQL the plan text contains the `WHERE` literals.

On `Special:Ask` the resulting string is concatenated into the page and sent through `OutputPage::addHTML`, never through the MediaWiki parser or Sanitizer. No special user right is required; an anonymous request suffices.

This is a reflected XSS: the payload is taken from the request and echoed in the same response. Exploitation requires the query condition to target a text/blob-typed property (whose value is re-serialized verbatim); the predefined `_txt` properties (`Text`, etc.) that ship on every install satisfy this, so no attacker-created content is needed. Example request:

``` Special:Ask?q=[[Text::<script>alert(document.domain)</script>]]&debug=1 ```

#### Remediation

- Apply output-context escapi…