A Denial of Service vulnerability exists in qs up to 6.8.0 due to insufficient sanitization of property in the gs.parse function. The merge() function allows the assignment of properties on an array in the query. For any property being assigned, a value in the array is converted to an object containing these properties. Essentially, this means that the property whose expected type is Array always has to be checked with Array.isArray() by the user. This may not be obvious to the user and can cause unexpected behavior.

** REJECT ** DO NOT USE THIS CANDIDATE NUMBER. ConsultIDs: none. Reason: This candidate was withdrawn by its CNA. Further investigation showed that it was not a security issue. Notes: none.

https://github.com/ljharb/qs/blob/master/dist/qs.js#L670 [Exploit, Third Party Advisory]

https://github.com/ljharb/qs/issues/436 [Issue Tracking, Third Party Advisory]

https://jsfiddle.net/65jxksay/ [Exploit, Third Party Advisory]

https://jsfiddle.net/pb6an1dy/ [Exploit, Third Party Advisory]