CVE-2026-74563

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

rds: tcp: hold the RCU lock across ipv6_chk_addr() in rds_tcp_laddr_check()

rds_tcp_laddr_check() looks up a scoped IPv6 interface with

dev_get_by_index_rcu(), drops the RCU read-side lock, and only then

passes the bare struct net_device * into ipv6_chk_addr().

dev_get_by_index_rcu() only keeps the device alive within the same RCU

read-side section. After rcu_read_unlock(), a concurrent RTM_DELLINK can

free the net_device; ipv6_chk_addr() then dereferences the stale pointer

in __ipv6_chk_addr_and_flags() (e.g. l3mdev_master_dev_rcu(dev)), reading

freed memory.

Keep the RCU read-side lock held across the ipv6_chk_addr() call instead

of dropping it right after the lookup, so the device cannot be freed

while it is in use.

BUG: KASAN: slab-use-after-free in __ipv6_chk_addr_and_flags (... net/ipv6/addrconf.c:1998)

Read of size 8 at addr ffff8880106ec000 by task exploit/153

Call Trace:

...

kasan_report (mm/kasan/report.c:595)

__ipv6_chk_addr_and_flags (... net/ipv6/addrconf.c:1998)

ipv6_chk_addr (net/ipv6/addrconf.c:2031 net/ipv6/addrconf.c:1972)

rds_tcp_laddr_check (net/rds/tcp.c:370)

rds_bind (net/rds/bind.c:248)

__sys_bind (net/socket.c:1920)

__x64_sys_bind (net/socket.c:1956)

do_syscall_64 (arch/x86/entry/syscall_64.c:63)

entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)