NASA did provide some explanations as given in the article itself
In the two right-eye images, the spot is in different locations of the image frame, and, in both cases, at the ground surface level in front of a crater rim on the horizon, Justin Maki, a NASA imaging scientist said April 8 by email through a spokesman.
"One possibility is that the light is the glint from a rock surface reflecting the sun," Maki said in the statement. "When these images were taken each day, the sun was in the same direction as the bright spot, west-northwest from the rover, and relatively low in the sky."
Another possibility is that the bright spots are sunlight reaching the camera's image sensor through a vent hole in the camera housing, which has happened before with Curiosity and other Mars rovers, the agency said.
"We think it's either a vent-hole light or a glinty rock," Maki said in the emailed statement. Another possibility is that it's a cosmic ray striking the camera's detector, he added.
Before NASA offered a suggestion of what might be the source of the bright spots, bloggers and space enthusiasts started chiming in.