I accidentally found a security issue while benchmarking postgres changes.
If you run debian testing, unstable or some other more "bleeding edge" distribution, I strongly recommend upgrading ASAP.
I was doing some micro-benchmarking at the time, needed to quiesce the system to reduce noise. Saw sshd processes were using a surprising amount of CPU, despite immediately failing because of wrong usernames etc. Profiled sshd, showing lots of cpu time in liblzma, with perf unable to attribute it to a symbol. Got suspicious. Recalled that I had seen an odd valgrind complaint in automated testing of postgres, a few weeks earlier, after package updates.
Really required a lot of coincidences.
@AndresFreundTec Oh, I didn't know you're on the fediverse! I embedded your post in my article @ https://boehs.org/node/everything-i-know-about-the-xz-backdoor
Please let me know if there's anything you'd like me to add to it or clarify!