Dates of French nuclear submarine's patrols accidentally leaked through fitness app: Report

Crew members of a French nuclear submarine inadvertently leaked the dates of their patrols through the fitness app Strava, according to an investigation by France's Le Monde daily.

The crew, stationed at the Ile Longue naval base near Brest on the west coast of France, were reportedly using the app to track their workouts.

The data, shared on their public profiles, could be accessed and exploited by other users, revealing details about submarine patrols, the report said Monday.

Although smartphones were largely banned on the base, the use of smartwatches --which can store and track information -- was overlooked, creating a security loophole.

Geolocation data from the devices unintentionally exposed movements of personnel, compromising what was considered a “fortress.”

The French Navy acknowledged the issue to Le Monde, confirming the oversight, but emphasized that there were no breaches affecting operational activities at the base.

An October 2024 report from Le Monde revealed that bodyguards of political leaders, including presidents, were unintentionally sharing their location data through Strava via mobile devices and smartwatches.

Despite its fitness focus, the app's geolocation features have raised concerns about broader security risks. The Le Monde report said the same fitness app was used by presidential security personnel, inadvertently exposing sensitive location data.