The governing FIA has confirmed all 2024 front wings are legal after Red Bull and Ferrari raised concerns about the designs of McLaren and Mercedes' cars.
Formula One's season has been turned upside down since Red Bull's dominant run at the start of the year, with McLaren and Mercedes claiming three wins each since the Miami Grand Prix in May.
McLaren is on pace to overtake Red Bull in the constructors' championship at the next race.
Red Bull and Ferrari have grown increasingly concerned by the front wing designs of both teams -- an onboard camera at the front of McLaren's car during first practice at the Italian Grand Prix showed it flexing down on the straights but returning to a more upright position in the Parabolica corner.
A certain degree of flexibility is allowed with front wings, but Red Bull and Ferrari believe McLaren and Mercedes' interpretations are beyond what the rules lay out.
Both teams were looking for clarity from the governing FIA as to whether the front wings are legal or not.
"The FIA is examining front wings at every event with numerous checks (conformity of surfaces, conformity of deflections) with respect to the relevant F1 Technical Regulation. All front wings are currently compliant with the 2024 regulations," The FIA said in a statement.
"Since the Belgium Grand Prix, the FIA has acquired additional data during FP1 and FP2 sessions to assess dynamic behaviours through an FIA-mandated video camera which captures areas of the front wing which are not visible through the official FOM cameras.
"This exercise will continue at least up until Singapore to ensure every team will have been running the mandated FIA camera on different types of tracks (low, medium, high and very high downforce).
"This will ensure a large database allowing the FIA to draw the most objective picture of the situation and quantify differences between the various dynamic patterns observed on track."
Red Bull boss Christian Horner had addressed the issue on Sunday night.
"I think the regs are very clear, I think that's an FIA issue, so obviously there's a test you pass and then you have to look at the wording of the regulations, if you remember back in '21 certainly around Baku time there was a change to the front wing regulation, even though our wing passed the test it was exploiting an elasticity so that's an FIA issue, we'll leave it with them," he said.
While McLaren and Mercedes have made huge steps forward in recent months, Red Bull has appeared to go in the opposite direction -- Max Verstappen said in Monza the team had turned its once-dominant car "into a monster."
Verstappen and Red Bull have not won a race since the Spanish Grand Prix in June.
Clarity on the flexibility of front wings might well encourage Red Bull to take a similar development path going forward.
"If it's acceptable you have to join it," Horner said.
Similarly, Ferrari has struggled to make clear steps forward with its car since winning at Monaco in May, although it claimed a surprise Italian Grand Prix win on Sunday after a one-stop strategy allowed Charles Leclerc to beat the McLaren cars.
Ferrari boss Fred Vasseur refused to comment on the front wing issue after the race, but indicated he was in communication with the FIA about it.
"This is a discussion that I don't want to have with you," Vasseur said. "I will have it with Nikolas Tombazis [FIA single seater director], but we have to respect the decision of the FIA that we will have again the discussion."