I wanted to mention WolfSSL.

I like to recommend that project because it has a very transparent vulnerabilities approach, and is in my opinion written a lot more sane than OpenSSL which is somewhat not using standard C features because it always implements everything from scratch like a kernel does.

But yeah, anyways, WolfSSL comes from the embedded area in case that's your thing.

[1] https://www.wolfssl.com/

[2] https://github.com/wolfssl/wolfssl