I have a suspicion that the bug is in the gcrypt library, not apt itself, but I haven't yet verified it. There's also debug.log which contains various versions, etc (although as I said, it has been verified on latest Ubuntu Live ISO). It's in the attachment alongside with an example file that causes this hash mismatch. I wrote the minimal reproducible example () that produces output such as this: It seems that calculating SHA1 and SHA256 the way APT does it produces wrong result, while running command line tools sha1sum and sha256sum (on the same PC inside the same VM) produces correct result. All of their hashes are correct (exactly as expected). I ran packet capture and extracted archives which are getting verified. On running 'apt update', there is an error 'Hash Sum mismatch' which shows that SHA1 and SHA256 hashes differ from expected (while MD5 and file size is correct). All testing was done in Virtualbox and moving VM's to another PC fixed issue (without changing anything inside the VM).

It also only occurs on a single PC (as far as I know).

This is a really weird bug that is happening on Ubuntu 20.04 LTS (Live ISO!!!) and Kali 2020.2, but not Debian 10 (so, it affects at least apt 2.0.2ubuntu0.1 and does not affect 1.8.2.1).

Kali linux virtualbox triggering atnit