CVE-2023-53200 netfilter: x_tables: fix percpu counter block leak on error path when creating new netns
A memory leak in the Linux kernel netfilter subsystem can lead to resource exhaustion and denial of service when creating new network namespaces.
- 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-2023-53200?
CVE-2023-53200 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:
netfilter: x_tables: fix percpu counter block leak on error path when creating new netns
Here is the stack where we allocate percpu counter block:
+-< __alloc_percpu +-< xt_percpu_counter_alloc +-< find_check_entry # {arp,ip,ip6}_tables.c +-< translate_table
And it can be leaked on this code path:
+-> ip6t_register_table +-> translate_table # allocates percpu counter block +-> xt_register_table # fails
there is no freeing of the counter block on xt_register_table fail. Note: xt_percpu_counter_free should be called to free it like we do in do_replace through cleanup_entry helper (or in __ip6t_unregister_table).
Probability of hitting this error path is low AFAICS (xt_register_table can only return ENOMEM here, as it is not replacing anything, as we are creating new netns, and it is hard to imagine that all previous allocations succeeded and after that one in xt_register_table failed). But it's worth fixing even the rare leak.
Weakness: CWE-401
Which versions are affected by CVE-2023-53200?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-53200?
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-2023-53200 being exploited?
There is no known exploitation of CVE-2023-53200 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2023-53200, DEBIAN-CVE-2023-53200, GHSA-hrpg-229c-xmmq, ROOT-OS-DEBIAN-11-CVE-2023-53200, UBUNTU-CVE-2023-53200.