In mathematics, we have lots of undergraduate research journals. In CS, you can publish by either conference proceedings or journal papers. Are there peer-reviewed conferences or journals aimed at research by undergraduate students? I am already aware of MCURCSM (but it didn't happen last year, and might not in 2019 either). Thanks!
I am not aware of any journals for undergraduate research journals in computer science. Note that anyone can submit to the journals and conferences, there can be student only papers.
ACM does have a student research competition at two levels, one for undergraduates and one for graduate students in computer science. Those are held at many conferences.
A number of CS conferences also have Poster Sessions at which work in progress, for example, can be presented. They may not have the same prestige as a full paper, but are useful for beginners at research to get feedback.
Another possibility, in the absence of specialized conferences for undergraduates is joint work with a professor at any conference.
But you don't need any credentials to submit to a CS conference (other than some interesting work). Interesting work by teams of students, with or without a professor as co-author, are another possibility.
If you are a professor that is familiar with some conference and its standards, there is no reason you can't have one or more of your students submit to it when you think it is ready for prime time. Even the experience of getting rejected can be useful to a beginner if the reviewers give helpful comments.