CVE-2023-53845 nilfs2: fix infinite loop in nilfs_mdt_get_block()
A corrupted nilfs2 disk image can cause an infinite loop and system hang in the Linux kernel, leading to 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-2023-53845?
CVE-2023-53845 is a denial of service vulnerability in Linux, published on 9 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:
nilfs2: fix infinite loop in nilfs_mdt_get_block()
If the disk image that nilfs2 mounts is corrupted and a virtual block address obtained by block lookup for a metadata file is invalid, nilfs_bmap_lookup_at_level() may return the same internal return code as -ENOENT, meaning the block does not exist in the metadata file.
This duplication of return codes confuses nilfs_mdt_get_block(), causing it to read and create a metadata block indefinitely.
In particular, if this happens to the inode metadata file, ifile, semaphore i_rwsem can be left held, causing task hangs in lock_mount.
Fix this issue by making nilfs_bmap_lookup_at_level() treat virtual block address translation failures with -ENOENT as metadata corruption instead of returning the error code.
Which versions are affected by CVE-2023-53845?
How do I fix CVE-2023-53845?
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-2023-53845 being exploited?
There is no known exploitation of CVE-2023-53845 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-53845, DEBIAN-CVE-2023-53845, GHSA-qv9p-mjrr-3vmm, UBUNTU-CVE-2023-53845.