CVE-2023-54185 btrfs: remove BUG_ON()'s in add_new_free_space()
A local attacker can trigger a kernel crash in the btrfs filesystem by exploiting missing error handling in free space management, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-54185?
CVE-2023-54185 is a denial of service vulnerability in Linux, published on 30 Dec 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:
btrfs: remove BUG_ON()'s in add_new_free_space()
At add_new_free_space() we have these BUG_ON()'s that are there to deal with any failure to add free space to the in memory free space cache. Such failures are mostly -ENOMEM that should be very rare. However there's no need to have these BUG_ON()'s, we can just return any error to the caller and all callers and their upper call chain are already dealing with errors.
So just make add_new_free_space() return any errors, while removing the BUG_ON()'s, and returning the total amount of added free space to an optional u64 pointer argument.
Which versions are affected by CVE-2023-54185?
How do I fix CVE-2023-54185?
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-2023-54185 being exploited?
There is no known exploitation of CVE-2023-54185 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-54185, DEBIAN-CVE-2023-54185, GHSA-px78-h2pc-q658, ROOT-OS-DEBIAN-11-CVE-2023-54185, ROOT-OS-UBUNTU-2204-CVE-2023-54185, UBUNTU-CVE-2023-54185.