CVE-2022-49561 netfilter: conntrack: re-fetch conntrack after insertion
A race condition in the Linux kernel netfilter conntrack module can lead to use-after-free issues, potentially causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-49561?
CVE-2022-49561 is a critical vulnerability in Linux kernel, published on 26 Feb 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
netfilter: conntrack: re-fetch conntrack after insertion
In case the conntrack is clashing, insertion can free skb->_nfct and set skb->_nfct to the already-confirmed entry.
This wasn't found before because the conntrack entry and the extension space used to free'd after an rcu grace period, plus the race needs events enabled to trigger.
Which versions are affected by CVE-2022-49561?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-49561?
Apply the vendor's patch.
Is CVE-2022-49561 being exploited?
There is no known exploitation of CVE-2022-49561 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-49561, GHSA-mwj5-hv79-wr7f, UBUNTU-CVE-2022-49561.