If your weep screed (the metal keeping your stucco from touching the ground) is rusted out, it’s best to replace it before water intrudes into your walls and house.
We are weep screed experts, why your weep screed rusted out should be easy to determine. Homes built before the mid 1980s likely won’t have weep screed as it was not yet mandatory to install.
Allowing stucco to go down to soil and allowing moisture to absorb into the plaster/stucco eventually disintegrates the building paper allowing water in. The remedy is to install or replace your weep screed.
Chip out stucco six inches above plate (mud seal) and chip cement off foundation install weep screed (top of weep screed level w/ top of plate (2×4). Tuck paper under existing paper over weep screed wire and patch, keep soil below weep screed.