CVE-2024-53690 nilfs2: prevent use of deleted inode
A use-after-free vulnerability in the nilfs2 filesystem allows local attackers to trigger a kernel warning and potential denial of service via corrupted inode bitmaps.
- 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-2024-53690?
CVE-2024-53690 is a medium-severity use after free vulnerability in Linux kernel, published on 11 Jan 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: prevent use of deleted inode
syzbot reported a WARNING in nilfs_rmdir. [1]
Because the inode bitmap is corrupted, an inode with an inode number that should exist as a ".nilfs" file was reassigned by nilfs_mkdir for "file0", causing an inode duplication during execution. And this causes an underflow of i_nlink in rmdir operations.
The inode is used twice by the same task to unmount and remove directories ".nilfs" and "file0", it trigger warning in nilfs_rmdir.
Avoid to this issue, check i_nlink in nilfs_iget(), if it is 0, it means that this inode has been deleted, and iput is executed to reclaim it.
[1] WARNING: CPU: 1 PID: 5824 at fs/inode.c:407 drop_nlink+0xc4/0x110 fs/inode.c:407 ... Call Trace: <TASK> nilfs_rmdir+0x1b0/0x250 fs/nilfs2/namei.c:342 vfs_rmdir+0x3a3/0x510 fs/namei.c:4394 do_rmdir+0x3b5/0x580 fs/namei.c:4453 __do_sys_rmdir fs/namei.c:4472 [inline] __se_sys_rmdir fs/namei.c:4470 [inline] __x64_sys_rmdir+0x47/0x50 fs/namei.c:4470 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f
Which versions are affected by CVE-2024-53690?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-53690?
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-2024-53690 being exploited?
There is no known exploitation of CVE-2024-53690 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2024-53690, DEBIAN-CVE-2024-53690, GHSA-497m-9xj2-rmhf, UBUNTU-CVE-2024-53690.