Disney reported on October 4 that Avengers: Endgame had overtaken Avatar again after the Endgame: Encore rerelease. The company put Endgame's worldwide total at an estimated $2.9255 billion, compared with Avatar's $2.9237 billion.
Those figures describe accumulated cinema revenue, rather than attendance or inflation-adjusted performance. They are Disney's dated estimate, not a new independently verified October 9 total. The narrow lead also means later rereleases could change the ranking.