CVE-2023-53172 fsverity: reject FS_IOC_ENABLE_VERITY on mode 3 fds
A local attacker can trigger a kernel warning and potential denial of service by calling FS_IOC_ENABLE_VERITY on an ioctl-only file descriptor.
- 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-2023-53172?
CVE-2023-53172 is a medium-severity vulnerability in Linux kernel, published on 15 Sep 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:
fsverity: reject FS_IOC_ENABLE_VERITY on mode 3 fds
Commit 56124d6c87fd ("fsverity: support enabling with tree block size < PAGE_SIZE") changed FS_IOC_ENABLE_VERITY to use __kernel_read() to read the file's data, instead of direct pagecache accesses.
An unintended consequence of this is that the 'WARN_ON_ONCE(!(file->f_mode & FMODE_READ))' in __kernel_read() became reachable by fuzz tests. This happens if FS_IOC_ENABLE_VERITY is called on a fd opened with access mode 3, which means "ioctl access only".
Arguably, FS_IOC_ENABLE_VERITY should work on ioctl-only fds. But ioctl-only fds are a weird Linux extension that is rarely used and that few people even know about. (The documentation for FS_IOC_ENABLE_VERITY even specifically says it requires O_RDONLY.) It's probably not worthwhile to make the ioctl internally open a new fd just to handle this case. Thus, just reject the ioctl on such fds for now.
Which versions are affected by CVE-2023-53172?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2023-53172?
Apply the vendor's patch.
Is CVE-2023-53172 being exploited?
There is no known exploitation of CVE-2023-53172 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2023-53172, DEBIAN-CVE-2023-53172, GHSA-f2h8-669r-j5fx, UBUNTU-CVE-2023-53172.