CVE-2024-42076: In the Linux kernel, the following vulnerability has been resolved: net: can: j1939: Initialize unused data in j1939_send_one() syzbot reported kern...

Description

In the Linux kernel, the following vulnerability has been resolved: net: can: j1939: Initialize unused data in j1939_send_one() syzbot reported kernel-infoleak in raw_recvmsg() [1]. j1939_send_one() creates full frame including unused data, but it doesn't initialize it. This causes the kernel-infoleak issue. Fix this by initializing unused data. [1] BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline] BUG: KMSAN: kernel-infoleak in copy_to_user_iter lib/iov_iter.c:24 [inline] BUG: KMSAN: kernel-infoleak in iterate_ubuf include/linux/iov_iter.h:29 [inline] BUG: KMSAN: kernel-infoleak in iterate_and_advance2 include/linux/iov_iter.h:245 [inline] BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:271 [inline] BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x366/0x2520 lib/iov_iter.c:185 instrument_copy_to_user include/linux/instrumented.h:114 [inline] copy_to_user_iter lib/iov_iter.c:24 [inline] iterate_ubuf include/linux/iov_iter.h:29 [inline] iterate_and_advance2 include/linux/iov_iter.h:245 [inline] iterate_and_advance include/linux/iov_iter.h:271 [inline] _copy_to_iter+0x366/0x2520 lib/iov_iter.c:185 copy_to_iter include/linux/uio.h:196 [inline] memcpy_to_msg include/linux/skbuff.h:4113 [inline] raw_recvmsg+0x2b8/0x9e0 net/can/raw.c:1008 sock_recvmsg_nosec net/socket.c:1046 [inline] sock_recvmsg+0x2c4/0x340 net/socket.c:1068 ____sys_recvmsg+0x18a/0x620 net/socket.c:2803 ___sys_recvmsg+0x223/0x840 net/socket.c:2845 do_recvmmsg+0x4fc/0xfd0 net/socket.c:2939 __sys_recvmmsg net/socket.c:3018 [inline] __do_sys_recvmmsg net/socket.c:3041 [inline] __se_sys_recvmmsg net/socket.c:3034 [inline] __x64_sys_recvmmsg+0x397/0x490 net/socket.c:3034 x64_sys_call+0xf6c/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:300 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:3804 [inline] slab_alloc_node mm/slub.c:3845 [inline] kmem_cache_alloc_node+0x613/0xc50 mm/slub.c:3888 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:577 __alloc_skb+0x35b/0x7a0 net/core/skbuff.c:668 alloc_skb include/linux/skbuff.h:1313 [inline] alloc_skb_with_frags+0xc8/0xbf0 net/core/skbuff.c:6504 sock_alloc_send_pskb+0xa81/0xbf0 net/core/sock.c:2795 sock_alloc_send_skb include/net/sock.h:1842 [inline] j1939_sk_alloc_skb net/can/j1939/socket.c:878 [inline] j1939_sk_send_loop net/can/j1939/socket.c:1142 [inline] j1939_sk_sendmsg+0xc0a/0x2730 net/can/j1939/socket.c:1277 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:745 ____sys_sendmsg+0x877/0xb60 net/socket.c:2584 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638 __sys_sendmsg net/socket.c:2667 [inline] __do_sys_sendmsg net/socket.c:2676 [inline] __se_sys_sendmsg net/socket.c:2674 [inline] __x64_sys_sendmsg+0x307/0x4a0 net/socket.c:2674 x64_sys_call+0xc4b/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Bytes 12-15 of 16 are uninitialized Memory access of size 16 starts at ffff888120969690 Data copied to user address 00000000200017c0 CPU: 1 PID: 5050 Comm: syz-executor198 Not tainted 6.9.0-rc5-syzkaller-00031-g71b1543c83d6 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024

Metrics

CVSS 3.1

5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.22%

13.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-908

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	< 5.4
Linux	Linux Kernel	>= 5.4.1, < 5.4.279
Linux	Linux Kernel	>= 5.5, < 5.10.221
Linux	Linux Kernel	>= 5.11, < 5.15.162
Linux	Linux Kernel	>= 5.16, < 6.1.97
Linux	Linux Kernel	>= 6.2, < 6.6.37
Linux	Linux Kernel	>= 6.7, < 6.9.8

References

Timeline

Published: Jul 29, 2024
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2024-42076?

In the Linux kernel, the following vulnerability has been resolved: net: can: j1939: Initialize unused data in j1939_send_one() syzbot reported kernel-infoleak in raw_recvmsg() [1]. j1939_send_one() creates full frame including unused data, but it doesn't initialize it. This causes the kernel-infoleak issue. Fix this by initializing unused data. [1] BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline] BUG: KMSAN: kernel-infoleak in copy_to_user_iter lib/iov_iter.c:24 [inline] BUG: KMSAN: kernel-infoleak in iterate_ubuf include/linux/iov_iter.h:29 [inline] BUG: KMSAN: kernel-infoleak in iterate_and_advance2 include/linux/iov_iter.h:245 [inline] BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:271 [inline] BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x366/0x2520 lib/iov_iter.c:185 instrument_copy_to_user include/linux/instrumented.h:114 [inline] copy_to_user_iter lib/iov_iter.c:24 [inline] iterate_ubuf include/linux/iov_iter.h:29 [inline] iterate_and_advance2 include/linux/iov_iter.h:245 [inline] iterate_and_advance include/linux/iov_iter.h:271 [inline] _copy_to_iter+0x366/0x2520 lib/iov_iter.c:185 copy_to_iter include/linux/uio.h:196 [inline] memcpy_to_msg include/linux/skbuff.h:4113 [inline] raw_recvmsg+0x2b8/0x9e0 net/can/raw.c:1008 sock_recvmsg_nosec net/socket.c:1046 [inline] sock_recvmsg+0x2c4/0x340 net/socket.c:1068 ____sys_recvmsg+0x18a/0x620 net/socket.c:2803 ___sys_recvmsg+0x223/0x840 net/socket.c:2845 do_recvmmsg+0x4fc/0xfd0 net/socket.c:2939 __sys_recvmmsg net/socket.c:3018 [inline] __do_sys_recvmmsg net/socket.c:3041 [inline] __se_sys_recvmmsg net/socket.c:3034 [inline] __x64_sys_recvmmsg+0x397/0x490 net/socket.c:3034 x64_sys_call+0xf6c/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:300 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:3804 [inline] slab_alloc_node mm/slub.c:3845 [inline] kmem_cache_alloc_node+0x613/0xc50 mm/slub.c:3888 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:577 __alloc_skb+0x35b/0x7a0 net/core/skbuff.c:668 alloc_skb include/linux/skbuff.h:1313 [inline] alloc_skb_with_frags+0xc8/0xbf0 net/core/skbuff.c:6504 sock_alloc_send_pskb+0xa81/0xbf0 net/core/sock.c:2795 sock_alloc_send_skb include/net/sock.h:1842 [inline] j1939_sk_alloc_skb net/can/j1939/socket.c:878 [inline] j1939_sk_send_loop net/can/j1939/socket.c:1142 [inline] j1939_sk_sendmsg+0xc0a/0x2730 net/can/j1939/socket.c:1277 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:745 ____sys_sendmsg+0x877/0xb60 net/socket.c:2584 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638 __sys_sendmsg net/socket.c:2667 [inline] __do_sys_sendmsg net/socket.c:2676 [inline] __se_sys_sendmsg net/socket.c:2674 [inline] __x64_sys_sendmsg+0x307/0x4a0 net/socket.c:2674 x64_sys_call+0xc4b/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Bytes 12-15 of 16 are uninitialized Memory access of size 16 starts at ffff888120969690 Data copied to user address 00000000200017c0 CPU: 1 PID: 5050 Comm: syz-executor198 Not tainted 6.9.0-rc5-syzkaller-00031-g71b1543c83d6 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024

How severe is CVE-2024-42076?

CVE-2024-42076 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.22% probability of exploitation in the next 30 days.

How do I fix CVE-2024-42076?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.