A 70-gigabyte data archive containing proprietary engineering documentation for the Boeing 737 and 787 aircraft programs has been listed for sale on the Darknet. The threat actor is demanding $200,000 for the stolen data, noting a willingness to negotiate the final price.

The breach reportedly impacted SEKISUI Aerospace, the U.S.-based subsidiary of Japan's Sekisui Chemical. The company manufactures composite and thermoplastic components for the aviation sector and serves as a tier-one supplier for Boeing's 737 and 787 manufacturing lines.

According to the seller, the compromised dataset includes PDF schematics, 3D models, STEP engineering files, component material specifications, equipment details, and manufacturing workflow guides. The files contain original Boeing cataloging references covering elements of the airframe, wings, structural framing, and cabin interiors.

Certain documents in the leak bear U.S. export control markings. If verified as authentic, the unauthorized distribution of these materials presents intellectual property risks and potential regulatory compliance violations regarding restricted technology transfers. While SEKISUI Aerospace also supplies organizations such as Spirit AeroSystems, Triumph Group, NASA, Lockheed Martin, and Northrop Grumman, there is currently no indication that data belonging to these entities was compromised.