{"id":"GHSA-q5fm-9mx6-44f4","aliases":["CVE-2026-77610"],"title":"Semantic MediaWiki has a query debug output XSS (`DebugFormatter`)","description":"## Query debug output XSS\n\n#### Failure mode\n\nSemantic 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:\n\n- `buildHTML()` echoes the re-serialized ASK query string escaping only `[`; `<`, `>`, `\"`, `'` pass through.\n- `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.\n- `prettifyExplain()` echoes `EXPLAIN` output; on PostgreSQL the plan text contains the `WHERE` literals.\n\nOn `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.\n\nThis 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:\n\n```\nSpecial:Ask?q=[[Text::<script>alert(document.domain)</script>]]&debug=1\n```\n\n#### Remediation\n\n- Apply output-context escaping at the `DebugFormatter` boundary. The `buildHTML()` contract already assumes its inputs are HTML-safe, but its callers do not honour that; escape each entry value on emission, and the SQL and `EXPLAIN` strings before they are wrapped.\n- Escaping only the query-string echo is insufficient: `prettifySQL()` and the \"Auxilliary Tables\" executed-query text carry the same attacker-controlled literals.\n\n#### Scope\n\nThe `prettifySPARQL()` sink already encodes `<` and `>` and is not affected. The same debug path is also reachable through inline `{{#ask:...|format=debug}}`, but that output returns into parser context and is sanitized there; the reflected `Special:Ask` path is the exposed sink.\n\n#### Relationship to GHSA-5jhc-3j2f-52rv\n\nThis issue was identified while splitting the consolidated report GHSA-5jhc-3j2f-52rv into per-vulnerability advisories. It is distinct from the four items in that report (plain table header, `sep`, `SearchByProperty` value, open redirect) and from `Special:Ask` form-input XSS (which is escaped separately).","severity":"medium","score":6.1,"published":"2026-09-18T16:53:23.000Z","modified":"2026-09-18T17:00:04.982Z","withdrawn":false,"knownExploited":false,"affected":[{"ecosystem":"Packagist","name":"mediawiki/semantic-media-wiki","ranges":[{"events":[{"introduced":"0"},{"fixed":"7.2.0"}],"type":"ECOSYSTEM"}],"versions":["1.9","1.9-RC1","1.9.0.1","1.9.0.2","1.9.1","1.9.1.1","1.9.2","1.9beta1","2.0","2.0-RC1","2.0-RC2","2.0-RC3","2.1.0","2.1.0-RC1","2.1.1","2.1.2","2.1.3","2.2.0","2.2.0-RC1","2.2.1","2.2.2","2.2.3","2.3.0","2.3.0-RC1","2.3.1","2.4.0","2.4.0-RC1","2.4.1","2.4.2","2.4.3","2.4.4","2.4.5","2.4.6","2.5.0","2.5.0-rc.1","2.5.1","2.5.2","2.5.3","2.5.4","2.5.5","2.5.6","2.5.7","2.5.8","3.0.0","3.0.0-rc.1","3.0.0-rc.2","3.0.1","3.0.2","3.1.0","3.1.0-rc.1","3.1.1","3.1.2","3.1.3","3.1.4","3.1.5","3.1.6","3.2.0","3.2.0-rc.1","3.2.0-rc.2","3.2.1","3.2.2","3.2.3","4.0.0","4.0.1","4.0.2","4.1.0","4.1.1","4.1.2","4.1.3","4.2.0","5.0.0","5.0.1","5.0.2","5.1.0","6.0.0","6.0.1","7.0.0","7.1.0"],"fixed":["7.2.0"]}],"references":["https://github.com/SemanticMediaWiki/SemanticMediaWiki/security/advisories/GHSA-q5fm-9mx6-44f4","https://github.com/SemanticMediaWiki/SemanticMediaWiki","https://github.com/SemanticMediaWiki/SemanticMediaWiki/releases/tag/7.2.0"],"sources":[{"name":"OSV","id":"GHSA-q5fm-9mx6-44f4","modified":"2026-09-18T17:00:04.982326153Z","url":"https://osv.dev/vulnerability/GHSA-q5fm-9mx6-44f4"}],"assessments":[{"source":"OSV","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1}]}