CVE-2022-49911 netfilter: ipset: enforce documented limit to prevent allocating huge memory
A local attacker can exhaust kernel memory by adding duplicate network entries to an ipset, 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-2022-49911?
CVE-2022-49911 is a medium-severity denial of service vulnerability in Linux kernel, published on 1 May 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: enforce documented limit to prevent allocating huge memory
Daniel Xu reported that the hash:net,iface type of the ipset subsystem does not limit adding the same network with different interfaces to a set, which can lead to huge memory usage or allocation failure.
The quick reproducer is
$ ipset create ACL.IN.ALL_PERMIT hash:net,iface hashsize 1048576 timeout 0 $ for i in $(seq 0 100); do /sbin/ipset add ACL.IN.ALL_PERMIT 0.0.0.0/0,kaf_$i timeout 0 -exist; done
The backtrace when vmalloc fails:
[Tue Oct 25 00:13:08 2022] ipset: vmalloc error: size 1073741848, exceeds total pages <...> [Tue Oct 25 00:13:08 2022] Call Trace: [Tue Oct 25 00:13:08 2022] <TASK> [Tue Oct 25 00:13:08 2022] dump_stack_lvl+0x48/0x60 [Tue Oct 25 00:13:08 2022] warn_alloc+0x155/0x180 [Tue Oct 25 00:13:08 2022] __vmalloc_node_range+0x72a/0x760 [Tue Oct 25 00:13:08 2022] ? hash_netiface4_add+0x7c0/0xb20 [Tue Oct 25 00:13:08 2022] ? __kmalloc_large_node+0x4a/0x90 [Tue Oct 25 00:13:08 2022] kvmalloc_node+0xa6/0xd0 [Tue Oct 25 00:13:08 2022] ? hash_netiface4_resize+0x99/0x710 <...>
The fix is to enforce the limit documented in the ipset(8) manpage:
> The internal restriction of the hash:net,iface set type is that the same > network prefix cannot be stored with more than 64 different interfaces > in a single set.
Which versions are affected by CVE-2022-49911?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-49911?
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-2022-49911 being exploited?
There is no known exploitation of CVE-2022-49911 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-49911, GHSA-wx74-4w24-9hwf, UBUNTU-CVE-2022-49911.