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Timatic has the following to say on Russian transit:
Transiting without a visa is possible for:
Holders of onward tickets for a max. transit time of 24 hours.
TWOV is not applicable if the airport of arrival is different from the airport of departure within the same Russian city.
There are no transit facilities available at Khabarovsk (KHV), Krasnodar (KRR), Mineralnye Vody (MRV), Rostov-on-Don (ROV), Sochi (AER), Vladivostok (VVO) and Yuzhno Sakhalinsk (UUS). Passengers are required to clear Immigration and Customs.
Therefore you will need a visa for a transit in Vladivostok. Transiting other airports (such as Moscow or St. Petersburg) should be fine however, as long as it's less than 24 hours.