# CVE-2023-53344: linux: In the Linux kernel, the following vulnerability has been resolved:  can: bcm: bcm_tx_setup(): fix KMSAN uninit-value...

CVE-2023-53344 is fixed in linux on 1 platform, first by DEBIAN-CVE-2023-53344, released September 17, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2023-53344
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0020
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 17, 2025

## Description

In the Linux kernel, the following vulnerability has been resolved:  can: bcm: bcm_tx_setup(): fix KMSAN uninit-value in vfs_write  Syzkaller reported the following issue:  ===================================================== BUG: KMSAN: uninit-value in aio_rw_done fs/aio.c:1520 [inline] BUG: KMSAN: uninit-value in aio_write+0x899/0x950 fs/aio.c:1600  aio_rw_done fs/aio.c:1520 [inline]  aio_write+0x899/0x950 fs/aio.c:1600  io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019  __do_sys_io_submit fs/aio.c:2078 [inline]  __se_sys_io_submit+0x293/0x770 fs/aio.c:2048  __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048  do_syscall_x64 arch/x86/entry/common.c:50 [inline]  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80  entry_SYSCALL_64_after_hwframe+0x63/0xcd  Uninit was created at:  slab_post_alloc_hook mm/slab.h:766 [inline]  slab_alloc_node mm/slub.c:3452 [inline]  __kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491  __do_kmalloc_node mm/slab_common.c:967 [inline]  __kmalloc+0x11d/0x3b0 mm/slab_common.c:981  kmalloc_array include/linux/slab.h:636 [inline]  bcm_tx_setup+0x80e/0x29d0 net/can/bcm.c:930  bcm_sendmsg+0x3a2/0xce0 net/can/bcm.c:1351  sock_sendmsg_nosec net/socket.c:714 [inline]  sock_sendmsg net/socket.c:734 [inline]  sock_write_iter+0x495/0x5e0 net/socket.c:1108  call_write_iter include/linux/fs.h:2189 [inline]  aio_write+0x63a/0x950 fs/aio.c:1600  io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019  __do_sys_io_submit fs/aio.c:2078 [inline]  __se_sys_io_submit+0x293/0x770 fs/aio.c:2048  __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048  do_syscall_x64 arch/x86/entry/common.c:50 [inline]  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80  entry_SYSCALL_64_after_hwframe+0x63/0xcd  CPU: 1 PID: 5034 Comm: syz-executor350 Not tainted 6.2.0-rc6-syzkaller-80422-geda666ff2276 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023 =====================================================  We can follow the call chain and find that 'bcm_tx_setup' function calls 'memcpy_from_msg' to copy some content to the newly allocated frame of 'op->frames'. After that the 'len' field of copied structure being compared with some constant value (64 or 8). However, if 'memcpy_from_msg' returns an error, we will compare some uninitialized memory. This triggers 'uninit-value' issue.  This patch will add 'memcpy_from_msg' possible errors processing to avoid uninit-value issue.  Tested via syzkaller

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.25-1 | [DEBIAN-CVE-2023-53344](https://patchblox.com/security/data/fix/linux/debian-cve-2023-53344.md) | Sep 17, 2025 |
| Linux | linux Debian 13.5 (trixie) | 6.1.25-1 | [DEBIAN-CVE-2023-53344](https://patchblox.com/security/data/fix/linux/debian-cve-2023-53344.md) | Sep 17, 2025 |
| Linux | linux Debian 14 | 6.1.25-1 | [DEBIAN-CVE-2023-53344](https://patchblox.com/security/data/fix/linux/debian-cve-2023-53344.md) | Sep 17, 2025 |

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