CVE-2024-26638 nbd: always initialize struct msghdr completely
An uninitialized memory bug in the Linux kernel's Network Block Device driver could allow local attackers to read sensitive kernel memory.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-26638?
CVE-2024-26638 is a medium-severity vulnerability in Linux kernel, published on 18 Mar 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
nbd: always initialize struct msghdr completely
syzbot complains that msg->msg_get_inq value can be uninitialized [1]
struct msghdr got many new fields recently, we should always make sure their values is zero by default.
[1] BUG: KMSAN: uninit-value in tcp_recvmsg+0x686/0xac0 net/ipv4/tcp.c:2571 tcp_recvmsg+0x686/0xac0 net/ipv4/tcp.c:2571 inet_recvmsg+0x131/0x580 net/ipv4/af_inet.c:879 sock_recvmsg_nosec net/socket.c:1044 [inline] sock_recvmsg+0x12b/0x1e0 net/socket.c:1066 __sock_xmit+0x236/0x5c0 drivers/block/nbd.c:538 nbd_read_reply drivers/block/nbd.c:732 [inline] recv_work+0x262/0x3100 drivers/block/nbd.c:863 process_one_work kernel/workqueue.c:2627 [inline] process_scheduled_works+0x104e/0x1e70 kernel/workqueue.c:2700 worker_thread+0xf45/0x1490 kernel/workqueue.c:2781 kthread+0x3ed/0x540 kernel/kthread.c:388 ret_from_fork+0x66/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:242
Local variable msg created at: __sock_xmit+0x4c/0x5c0 drivers/block/nbd.c:513 nbd_read_reply drivers/block/nbd.c:732 [inline] recv_work+0x262/0x3100 drivers/block/nbd.c:863
CPU: 1 PID: 7465 Comm: kworker/u5:1 Not tainted 6.7.0-rc7-syzkaller-00041-gf016f7547aee #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 Workqueue: nbd5-recv recv_work
Weakness: CWE-908
Which versions are affected by CVE-2024-26638?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-26638?
Apply the vendor's patch.
Is CVE-2024-26638 being exploited?
There is no known exploitation of CVE-2024-26638 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2024-26638, DEBIAN-CVE-2024-26638, GHSA-c8gp-pfr5-2mm3, UBUNTU-CVE-2024-26638.