CVE-2022-48809 net: fix a memleak when uncloning an skb dst and its metadata
A memory leak in the Linux kernel network stack can lead to resource exhaustion and 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-2022-48809?
CVE-2022-48809 is a medium-severity denial of service vulnerability in Linux kernel, published on 16 Jul 2024. 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:
net: fix a memleak when uncloning an skb dst and its metadata
When uncloning an skb dst and its associated metadata, a new dst+metadata is allocated and later replaces the old one in the skb. This is helpful to have a non-shared dst+metadata attached to a specific skb.
The issue is the uncloned dst+metadata is initialized with a refcount of 1, which is increased to 2 before attaching it to the skb. When tun_dst_unclone returns, the dst+metadata is only referenced from a single place (the skb) while its refcount is 2. Its refcount will never drop to 0 (when the skb is consumed), leading to a memory leak.
Fix this by removing the call to dst_hold in tun_dst_unclone, as the dst+metadata refcount is already 1.
Weakness: CWE-401
Which versions are affected by CVE-2022-48809?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-48809?
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-2022-48809 being exploited?
There is no known exploitation of CVE-2022-48809 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-48809, GHSA-7jv7-gr8j-4554, UBUNTU-CVE-2022-48809.