A massive data breach targeting Russia's Federal State Statistics Service, known as Rosstat, has uncovered internal documents indicating that Russian military fatalities in Ukraine have far exceeded previous official acknowledgments, according to two hacker groups. The groups, identified as Kiberpartizany BY and Silent Crow, claimed responsibility for infiltrating the state statistics agency and exfiltrating approximately 23 terabytes of records. The stolen dataset includes internal files, economic and demographic statistics, and detailed records on Russian casualties stemming from the full-scale invasion of Ukraine launched in February 2022.
Analyzing the exfiltrated materials, Kiberpartizany BY calculated that at least 393,881 Russian citizens had been killed in the war as of August 27, 2026. That estimate focused specifically on recorded fatalities where military action or its direct consequences were formally documented as the cause of death. Meanwhile, Silent Crow projected an even higher total of 450,100 deaths. The disparity between the two totals stems from differing counting methodologies: Silent Crow included combat deaths alongside non-combat military fatalities, deaths classified as terrorist acts, and fatalities involving individuals registered in Russia who died in Ukraine or occupied territories without an established cause of death.
The newly leaked figures emerge at a time when transparent information on Russian military losses remains extremely scarce. The Russian government has not released official statistical updates on its combat casualties since September 2022, and Rosstat stopped making its annual cause-of-death data public in 2024, severely hindering independent attempts to assess the demographic impact of the war. Against this backdrop, access to internal state statistical materials could provide a significantly clearer picture of the true human cost.
Prior to the breach disclosure, a joint tracking project by Mediazona and the BBC News Russian Service had compiled a database containing roughly 286,000 names of confirmed Russian servicemen killed in action as of November 8, though researchers note that list is inherently incomplete, particularly for recent combat months. Additionally, a separate joint study by Meduza and Mediazona using inheritance registry data estimated that approximately 350,000 Russian servicemen had fallen by the end of 2025. While the hackers' figures align broadly with the general trajectories of these prior studies, experts note that such alignment does not yet confirm the precision of every individual number.
Independent investigative outlets Meduza and Mediazona confirmed they have obtained access to the dataset published by the hackers and have begun a thorough verification process. Journalists are evaluating the files to confirm their authenticity and completeness while attempting to rule out deliberate data manipulation. Experts also emphasize that internal state records carry inherent caveats: medical death certificates do not always reflect actual death circumstances, and Rosstat's databases do not track individuals listed as missing in action, who are declared dead only after lengthy legal procedures. Nevertheless, if verified, the exfiltrated records could become one of the largest available disclosures on the demographic consequences of the war for Russia.
