# CVE-2023-53344: can: bcm: bcm_tx_setup(): fix KMSAN uninit-value in vfs_write

> A local attacker can trigger an uninitialized value bug in the Linux kernel CAN BCM module to potentially read sensitive kernel memory.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-53344, DEBIAN-CVE-2023-53344, GHSA-7qp3-gx4r-g85j, UBUNTU-CVE-2023-53344

## What is CVE-2023-53344?

CVE-2023-53344 is a medium-severity vulnerability in Linux kernel, published on 17 Sep 2025. 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:

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

Weakness: CWE-908 (Use of Uninitialized Resource)

## Which versions are affected by CVE-2023-53344?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-53344?

Apply the vendor's patch.

## Is CVE-2023-53344 being exploited?

There is no known exploitation of CVE-2023-53344 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-53344 and fix it if it is affected.

What it is: CVE-2023-53344 is a medium-severity vulnerability in Linux kernel, published on 17 Sep 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-53344 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-53344/ (Markdown: https://insights.sbomify.com/CVE-2023-53344/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53344
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53344
- OSV: https://osv.dev/vulnerability/CVE-2023-53344

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-53344/
Summaries are generated and may contain mistakes; the official description above is the record.