The measure, which includes only voluntary procedures for sharing information and no mandates, has broad support in the private sector.
But privacy advocates, including the American Civil Liberties Union, the Center for Democracy and Technology and the Electronic Frontier Foundation, are lobbying against CISPA, warning that it would lead companies to hand over their customers' private information to military spy agencies.
The White House has threatened to veto CISPA, saying it lacks adequate privacy protections and fails to protect critical infrastructure, such as electrical grids, banks and chemical plants.
Despite the veto threat, the House approved CISPA last week on a vote of 248-168. The White House and Senate Democratic leaders back a bill from Sens. Joe Lieberman (I-Conn.) and Susan Collins (Maine) that includes tougher privacy protections and would set mandatory security standards for critical infrastructure systems.
Mozilla's statement was first reported by Forbes.