A flaw was found in the Linux kernel Traffic Control (TC) subsystem. Using a specific networking configuration (redirecting egress packets to ingress using TC action "mirred") a local unprivileged user could trigger a CPU soft lockup (ABBA deadlock) when the transport protocol in use (TCP or SCTP) does a retransmission, resulting in a denial of service condition.
https://www.debian.org/security/2023/dsa-5480
https://security.netapp.com/advisory/ntap-20230929-0001/
https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html