As Facebook grapples with a backlash over its role in spreading disinformation, an internal dispute over how to handle the threat and the public outcry is resulting in the departure of a senior executive.

The impending exit of that executive — Alex Stamos, Facebook’s chief information security officer — reflects heightened leadership tension at the top of the social network. Much of the internal disagreement is rooted in how much Facebook should publicly share about how nation states misused the platform and debate over organizational changes in the run-up to the 2018 midterm elections, according to current and former employees briefed on the matter.

Mr. Stamos, who plans to leave Facebook by August, had advocated more disclosure around Russian interference of the platform and some restructuring to better address the issues, but was met with resistance by colleagues, said the current and former employees. In December, Mr. Stamos’s day-to-day responsibilities were reassigned to others, they said.

Mr. Stamos said he would leave Facebook but was persuaded to stay through August to oversee the transition of his responsibilities and because executives thought his departure would look bad, the people said. He has been overseeing the transfer of his security team to Facebook’s product and infrastructure divisions. His group, which once had 120 people, now has three, the current and former employees said.