"Impacted" meaning that there are more applications from qualified applicants than there are available spaces.
Impaction also means that campuses can--and do--often invoke what's called "supplementary admission criteria" either for the program or for students who don't reside in the campus's local area. This means that the campus requires higher standards for admitting students when it is impacted (e.g. Higher GPA).
The CSU campuses that are impacted at all levels and all programs are
Cal Poly San Luis Obispo
Fresno State
CSU Fullerton
Cal State LA
CSU Long Beach
San Diego State University
San José State