Average 30-year fixed mortgage rates rose 0.04 percentage point to 6.60% at the start of the week, reversing part of last week's drop.
Iranian officials said peace negotiations were effectively tabled while Israel-Lebanon hostilities continue, triggering an immediate jump in oil prices and a selloff in bonds.
Higher fuel costs feed inflation fears, and bond weakness pushes mortgage pricing higher because mortgage rates track bond-market moves.
The increase was relatively mild: 6.60% remains 0.10 percentage point below the recent 6.70% peak reached on May 19.