GHSA-mp7w-mhcv-673j Vega allows Cross-site Scripting via the vlSelectionTuples function

• npm vega: < 5.26.0 → fixed in 5.26.0 • npm vega-selections: < 5.4.2 → fixed in 5.4.2

Summary The `vlSelectionTuples` function can be used to call JavaScript functions, leading to XSS. Details `vlSelectionTuples` calls multiple functions that can be controlled by an attacker, including one call with an attacker-controlled argument. Example call: `vlSelectionTuples([{datum:}], {fields:[{getter:}]})` This can be used to call `Function()` with arbitrary JavaScript and the resulting function can be called with `vlSelectionTuples` or using a type coercion to call `toString` or `valueOf`. PoC ``` {"$schema":"https://vega.github.io/schema/vega/v5.json","signals":[{"name":"a","init":"+{valueOf:vlSelectionTuples([{datum:'alert(1)'}],{fields:[{getter:[].at.constructor}]})[0].values[0]}"}]} ```