SPIP before 4.1.14 and 4.2.x before 4.2.8 allows XSS via the name of an uploaded file. This is related to javascript/bigup.js and javascript/bigup.utils.js.
https://git.spip.net/spip/bigup/commit/ada821c076d67d1147a195178223d0b4a6d8cecc
https://git.spip.net/spip/bigup/commit/0757f015717cb72b84dba0e9a375ec71caddf1c2