CVE-2022-50314 nbd: Fix hung when signal interrupts nbd_start_device_ioctl()
A local attacker can cause a system hang in the Linux kernel NBD driver by interrupting a specific ioctl call with a signal.
- 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-2022-50314?
CVE-2022-50314 is a medium-severity denial of service vulnerability in Linux kernel, published on 15 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:
nbd: Fix hung when signal interrupts nbd_start_device_ioctl()
syzbot reported hung task [1]. The following program is a simplified version of the reproducer:
int main(void) { int sv[2], fd;
if (socketpair(AF_UNIX, SOCK_STREAM, 0, sv) < 0) return 1; if ((fd = open("/dev/nbd0", 0)) < 0) return 1; if (ioctl(fd, NBD_SET_SIZE_BLOCKS, 0x81) < 0) return 1; if (ioctl(fd, NBD_SET_SOCK, sv[0]) < 0) return 1; if (ioctl(fd, NBD_DO_IT) < 0) return 1; return 0; }
When signal interrupt nbd_start_device_ioctl() waiting the condition atomic_read(&config->recv_threads) == 0, the task can hung because it waits the completion of the inflight IOs.
This patch fixes the issue by clearing queue, not just shutdown, when signal interrupt nbd_start_device_ioctl().
Which versions are affected by CVE-2022-50314?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-50314?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2022-50314 being exploited?
There is no known exploitation of CVE-2022-50314 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-50314, GHSA-x3q5-jcq9-7rv7, UBUNTU-CVE-2022-50314.