Seated Nude is a portrait by the Russian artist Victor Stember.
103.7 by 80.7 cm, signed “ВШтемберъ” (Stember, in the pre-1918 Russian spelling). Reproduced on Wikimedia Commons and the Russian dealer site art-globe.ru, both giving the same specific measurements, which do not match any nude already in the catalog.
Do you have information about this portrait, such as its location, provenance, or a better photograph? Please contact the family.