CVE-2025-39812sctp: initialize more fields in sctp_v6_from_sk()

Official description

In the Linux kernel, the following vulnerability has been resolved: sctp: initialize more fields in sctp_v6_from_sk() syzbot found that sin6_scope_id was not properly initialized, leading to undefined behavior. Clear sin6_scope_id and sin6_flowinfo. BUG: KMSAN: uninit-value in __sctp_v6_cmp_addr+0x887/0x8c0 net/sctp/ipv6.c:649 __sctp_v6_cmp_addr+0x887/0x8c0 net/sctp/ipv6.c:649 sctp_inet6_cmp_addr+0x4f2/0x510 net/sctp/ipv6.c:983 sctp_bind_addr_conflict+0x22a/0x3b0 net/sctp/bind_addr.c:390 sctp_get_port_local+0x21eb/0x2440 net/sctp/socket.c:8452 sctp_get_port net/sctp/socket.c:8523 [inline] sctp_listen_start net/sctp/socket.c:8567 [inline] sctp_inet_listen+0x710/0xfd0 net/sctp/socket.c:8636 __sys_listen_socket net/socket.c:1912 [inline] __sys_listen net/socket.c:1927 [inline] __do_sys_listen net/socket.c:1932 [inline] __se_sys_listen net/socket.c:1930 [inline] __x64_sys_listen+0x343/0x4c0 net/socket.c:1930 x64_sys_call+0x271d/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:51 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Local variable addr.i.i created at: sctp_get_port net/sctp/socket.c:8515 [inline] sctp_listen_start net/sctp/socket.c:8567 [inline] sctp_inet_listen+0x650/0xfd0 net/sctp/socket.c:8636 __sys_listen_socket net/socket.c:1912 [inline] __sys_listen net/socket.c:1927 [inline] __do_sys_listen net/socket.c:1932 [inline] __se_sys_listen net/socket.c:1930 [inline] __x64_sys_listen+0x343/0x4c0 net/socket.c:1930

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/45e4b36593edffb7bbee5828ae820bc10a9fa0f3
• https://git.kernel.org/stable/c/9546934c2054bba1bd605c44e936619159a34027
• https://git.kernel.org/stable/c/17d6c7747045e9b802c2f5dfaba260d309d831ae
• https://git.kernel.org/stable/c/65b4693d8bab5370cfcb44a275b4d8dcb06e56bf
• https://git.kernel.org/stable/c/463aa96fca6209bb205f49f7deea3817d7ddaa3a
• https://git.kernel.org/stable/c/1bbc0c02aea1f1c405bd1271466889c25a1fe01b
• https://git.kernel.org/stable/c/f6c2cc99fc2387ba6499facd6108f6543382792d
• https://git.kernel.org/stable/c/2e8750469242cad8f01f320131fd5a6f540dbb99
• https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
• https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html
• https://cert-portal.siemens.com/productcert/html/ssa-032379.html