2020.06.20 21:23:37 (1274422674840711168) from Daniel J. Bernstein:
This is clearly not the world's biggest problem in 2020, but it's still depressing to see the official software for Frodo (a high-profile candidate for post-quantum crypto) broken by a timing attack on memcmp: https://eprint.iacr.org/2020/743.pdf. We need more work on constant-time languages.