Didn't take a course I planned to take on my CSU application

I was supposed to retake a semester of Geometry but it wasn’t fathomable with my class schedule. My major is in English and my math throughout highschool looks like this:
Algebra 1 Pre AP B- D+
Alg 2 CP C C-
Geometry C- ( this second semester is the one I didn’t pass and was supposed to retake)
Trig D- (this grade will be known once the semester is over)

will me not taking the geometry result in my acceptance being reincided from a school like East Bay or Stanislaus? My passing grade this semester in Trig is supposed to validate the first semester from what the counselor told me. Should I call my East Bay and Stanislaus to let them know?..

This is the CSU requirements for Math:
Math (4 years recommended) including Algebra I, Geometry, Algebra II, or higher mathematics (take one each year)

Geometry is a required Math course for the Cal States. Unless you pass, I would say that your admission is in jeopardy since you do not meet the minimum. Yes, I would contact East Bay and Stanislaus. They may let you take it during the Summer or once you are on campus. Since both schools are not impacted, they may be more lenient than others but definitely address this issue now.

I got a D second semester in geometry, should I simply allow them to fill that score in instead?

they will probably rescind but, you need to call and ask what they suggest you do. There may be an on-line option or something. Not sure what you want to study but, some level of foundational math is likely to be required. I’d say you may be best served at a CC (which is significantly cheaper) where you can build the capabilities need to get through your college course load.

Yes, they could rescind your acceptance. I’m pretty sure you have to let them know about any schedule changes.