A Fajr prayer has reached its closing Salaam, but Sujud al-Sahw is still pending. The sun then rises. What happens?

Sujud al-Sahw: Cause, Method, Timing, and Special Cases

• The pending Sujud al-Sahw drops; this rule does not mean the completed Fajr itself becomes invalid.
• The completed Fajr automatically becomes invalid only because the sun rose after Salaam.
• The prayer becomes Zuhr.
• A new Adhan is the only remedy.