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 ("Double-Hash Port Selection Algorithm") of RFC 6056.
Exploitability
AV:LAC:LPR:LUI:NScope
S:UImpact
C:LI:NA:N3.3/CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N