CVE-2024-50186 net: explicitly clear the sk pointer, when pf->create fails
A use-after-free vulnerability in the Linux kernel network subsystem allows attackers to potentially execute code or escalate privileges via crafted socket creation failures.
- 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-2024-50186?
CVE-2024-50186 is a high-severity use after free vulnerability in Linux kernel, published on 8 Nov 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: explicitly clear the sk pointer, when pf->create fails
We have recently noticed the exact same KASAN splat as in commit 6cd4a78d962b ("net: do not leave a dangling sk pointer, when socket creation fails"). The problem is that commit did not fully address the problem, as some pf->create implementations do not use sk_common_release in their error paths.
For example, we can use the same reproducer as in the above commit, but changing ping to arping. arping uses AF_PACKET socket and if packet_create fails, it will just sk_free the allocated sk object.
While we could chase all the pf->create implementations and make sure they NULL the freed sk object on error from the socket, we can't guarantee future protocols will not make the same mistake.
So it is easier to just explicitly NULL the sk pointer upon return from pf->create in __sock_create. We do know that pf->create always releases the allocated sk object on error, so if the pointer is not NULL, it is definitely dangling.
Weakness: CWE-416
Which versions are affected by CVE-2024-50186?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-50186?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2024-50186 being exploited?
There is no known exploitation of CVE-2024-50186 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2024-50186, DEBIAN-CVE-2024-50186, GHSA-68xx-p949-f9wp, UBUNTU-CVE-2024-50186.