CVE-2022-49085 drbd: Fix five use after free bugs in get_initial_state
A use-after-free vulnerability in the Linux kernel's DRBD module allows attackers to cause denial of service or potentially execute code.
- 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-2022-49085?
CVE-2022-49085 is a high-severity use after free vulnerability in Linux kernel, published on 26 Feb 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:
drbd: Fix five use after free bugs in get_initial_state
In get_initial_state, it calls notify_initial_state_done(skb,..) if cb->args[5]==1. If genlmsg_put() failed in notify_initial_state_done(), the skb will be freed by nlmsg_free(skb). Then get_initial_state will goto out and the freed skb will be used by return value skb->len, which is a uaf bug.
What's worse, the same problem goes even further: skb can also be freed in the notify_*_state_change -> notify_*_state calls below. Thus 4 additional uaf bugs happened.
My patch lets the problem callee functions: notify_initial_state_done and notify_*_state_change return an error code if errors happen. So that the error codes could be propagated and the uaf bugs can be avoid.
v2 reports a compilation warning. This v3 fixed this warning and built successfully in my local environment with no additional warnings. v2: https://lore.kernel.org/patchwork/patch/1435218/
Weakness: CWE-416
Which versions are affected by CVE-2022-49085?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-49085?
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-2022-49085 being exploited?
There is no known exploitation of CVE-2022-49085 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-49085, GHSA-vcqr-h4qj-jv8g, UBUNTU-CVE-2022-49085.