CVE-2023-53549 netfilter: ipset: Rework long task execution when adding/deleting entries
An attacker can cause a denial of service via soft lockups by adding or deleting large numbers of elements in ipset.
- 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-2023-53549?
CVE-2023-53549 is a medium-severity denial of service vulnerability in Linux kernel, published on 4 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:
netfilter: ipset: Rework long task execution when adding/deleting entries
When adding/deleting large number of elements in one step in ipset, it can take a reasonable amount of time and can result in soft lockup errors. The patch 5f7b51bf09ba ("netfilter: ipset: Limit the maximal range of consecutive elements to add/delete") tried to fix it by limiting the max elements to process at all. However it was not enough, it is still possible that we get hung tasks. Lowering the limit is not reasonable, so the approach in this patch is as follows: rely on the method used at resizing sets and save the state when we reach a smaller internal batch limit, unlock/lock and proceed from the saved state. Thus we can avoid long continuous tasks and at the same time removed the limit to add/delete large number of elements in one step.
The nfnl mutex is held during the whole operation which prevents one to issue other ipset commands in parallel.
Weakness: CWE-667
Which versions are affected by CVE-2023-53549?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-53549?
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-2023-53549 being exploited?
There is no known exploitation of CVE-2023-53549 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2023-53549, DEBIAN-CVE-2023-53549, GHSA-ff5r-w44x-rq6x, UBUNTU-CVE-2023-53549.