In the second round of qualifying, Massa, driving his Ferrari, ran off the course in turn four and slammed head-on into the tire barrier after being struck on the head by a spring that came off the Brawn GP car driven by Rubens Barrichello.
Massa, a native of Sao Paulo, underwent surgery at the AEK Hospital in Budapest, the team said in a statement late Saturday. He remained under observation in intensive care and in a "life-threatening" condition, though the outcome of his surgery was called "positive."
Massa, 28, also suffered a concussion and a cut on his forehead. He was conscious when he was flown to the hospital by helicopter.
Massa is fifth in the latest F1 standings with 22 points.