The Linux kernel before 5.17.9 allows TCP servers to identify clients by observing what source ports are used. This occurs because of use of Algorithm 4 (βDouble-Hash Port Selection Algorithmβ) of RFC 6056.
arxiv.org/abs/2209.12993
cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.17.9
git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=4c2c8f03a5ab7cb04ec64724d7d176d00bcc91e5
github.com/0xkol/rfc6056-device-tracker
lists.debian.org/debian-lts-announce/2022/07/msg00000.html
www.debian.org/security/2022/dsa-5173