CVE-2023-53731 netlink: fix potential deadlock in netlink_set_err()
A local attacker can trigger a deadlock in the Linux kernel netlink subsystem, causing a denial of service.
- 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
What is CVE-2023-53731?
CVE-2023-53731 is a vulnerability in Linux, published on 22 Oct 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:
netlink: fix potential deadlock in netlink_set_err()
syzbot reported a possible deadlock in netlink_set_err() [1]
A similar issue was fixed in commit 1d482e666b8e ("netlink: disable IRQs for netlink_lock_table()") in netlink_lock_table()
This patch adds IRQ safety to netlink_set_err() and __netlink_diag_dump() which were not covered by cited commit.
[1]
WARNING: possible irq lock inversion dependency detected 6.4.0-rc6-syzkaller-00240-g4e9f0ec38852 #0 Not tainted
syz-executor.2/23011 just changed the state of lock: ffffffff8e1a7a58 (nl_table_lock){.+.?}-{2:2}, at: netlink_set_err+0x2e/0x3a0 net/netlink/af_netlink.c:1612 but this lock was taken by another, SOFTIRQ-safe lock in the past: (&local->queue_stop_reason_lock){..-.}-{2:2}
and interrupts could create inverse lock ordering between them.
other info that might help us debug this: Possible interrupt unsafe locking scenario:
CPU0 CPU1 ---- ---- lock(nl_table_lock); local_irq_disable(); lock(&local->queue_stop_reason_lock); lock(nl_table_lock); <Interrupt> lock(&local->queue_stop_reason_lock);
*** DEADLOCK ***
Which versions are affected by CVE-2023-53731?
How do I fix CVE-2023-53731?
Apply the vendor's patch.
Is CVE-2023-53731 being exploited?
There is no known exploitation of CVE-2023-53731 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-53731, DEBIAN-CVE-2023-53731, GHSA-cj8f-58h8-h475, UBUNTU-CVE-2023-53731.