CVE-2026-68290

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

rds: tcp: unregister sysctl before tearing down listen socket

rds_tcp_exit_net() frees the per-netns RDS TCP listen socket via

rds_tcp_kill_sock() before unregistering the per-netns sysctl table. Since

rds_tcp_skbuf_handler() derives the netns from

rtn->rds_tcp_listen_sock->sk, a concurrent sysctl write can race with

netns teardown and dereference the freed socket/sk.

KASAN reports the race as:

BUG: KASAN: slab-use-after-free in rds_tcp_skbuf_handler+0x2aa/0x2e0

rds_tcp_skbuf_handler net/rds/tcp.c:721

proc_sys_call_handler fs/proc/proc_sysctl.c

vfs_write fs/read_write.c

__x64_sys_pwrite64 fs/read_write.c

Fix this by unregistering the RDS TCP sysctl table before calling

rds_tcp_kill_sock(). unregister_net_sysctl_table() prevents new sysctl

handlers from starting and waits for in-flight handlers to finish, so

the listen socket can then be

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References