VitaFit cloud API before 2026-10-30 contained an improper access control vulnerability in its Cognito-issued AWS role that allows authenticated attackers to perform s3:PutObject operations across the entire shared bucket instead of being restricted to their own folder. Attackers can overwrite other users' objects in the shared S3 bucket using credentials obtained via CVE-2026-54378, destroying original content without triggering deletion protections.