# CVE-2024-53219: virtiofs: use pages instead of pointer for kernel direct IO

> A flaw in the Linux kernel virtiofs driver causes a warning and potential instability when loading large kernel modules from a cache-disabled virtio-fs mount.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **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:** Yes
- **Published:** 27 Dec 2024
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-62565, AZL-67605, BELL-CVE-2024-53219, DEBIAN-CVE-2024-53219, GHSA-8r65-896m-pfq8, ROOT-OS-DEBIAN-11-CVE-2024-53219, ROOT-OS-DEBIAN-12-CVE-2024-53219, ROOT-OS-UBUNTU-2204-CVE-2024-53219, UBUNTU-CVE-2024-53219

## What is CVE-2024-53219?

CVE-2024-53219 is a medium-severity denial of service vulnerability in Linux kernel, published on 27 Dec 2024. 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:

virtiofs: use pages instead of pointer for kernel direct IO

When trying to insert a 10MB kernel module kept in a virtio-fs with cache
disabled, the following warning was reported:

  ------------[ cut here ]------------
  WARNING: CPU: 1 PID: 404 at mm/page_alloc.c:4551 ......
  Modules linked in:
  CPU: 1 PID: 404 Comm: insmod Not tainted 6.9.0-rc5+ #123
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ......
  RIP: 0010:__alloc_pages+0x2bf/0x380
  ......
  Call Trace:
   <TASK>
   ? __warn+0x8e/0x150
   ? __alloc_pages+0x2bf/0x380
   __kmalloc_large_node+0x86/0x160
   __kmalloc+0x33c/0x480
   virtio_fs_enqueue_req+0x240/0x6d0
   virtio_fs_wake_pending_and_unlock+0x7f/0x190
   queue_request_and_unlock+0x55/0x60
   fuse_simple_request+0x152/0x2b0
   fuse_direct_io+0x5d2/0x8c0
   fuse_file_read_iter+0x121/0x160
   __kernel_read+0x151/0x2d0
   kernel_read+0x45/0x50
   kernel_read_file+0x1a9/0x2a0
   init_module_from_file+0x6a/0xe0
   idempotent_init_module+0x175/0x230
   __x64_sys_finit_module+0x5d/0xb0
   x64_sys_call+0x1c3/0x9e0
   do_syscall_64+0x3d/0xc0
   entry_SYSCALL_64_after_hwframe+0x4b/0x53
   ......
   </TASK>
  ---[ end trace 0000000000000000 ]---

The warning is triggered as follows:

1) syscall finit_module() handles the module insertion and it invokes
kernel_read_file() to read the content of the module first.

2) kernel_read_file() allocates a 10MB buffer by using vmalloc() and
passes it to kernel_read(). kernel_read() constructs a kvec iter by
using iov_iter_kvec() and passes it to fuse_file_read_iter().

3) virtio-fs disables the cache, so fuse_file_read_iter() invokes
fuse_direct_io(). As for now, the maximal read size for kvec iter is
only limited by fc->max_read. For virtio-fs, max_read is UINT_MAX, so
fuse_direct_io() doesn't split the 10MB buffer. It saves the address and
the size of the 10MB-sized buffer in out_args[0] of a fuse request and
passes the fuse request to virtio_fs_wake_pending_and_unlock().

4) virtio_fs_wake_pending_and_unlock() uses virtio_fs_enqueue_req() to
queue the request. Because virtiofs need DMA-able address, so
virtio_fs_enqueue_req() uses kmalloc() to allocate a bounce buffer for
all fuse args, copies these args into the bounce buffer and passed the
physical address of the bounce buffer to virtiofsd. The total length of
these fuse args for the passed fuse request is about 10MB, so
copy_args_to_argbuf() invokes kmalloc() with a 10MB size parameter and
it triggers the warning in __alloc_pages():

	if (WARN_ON_ONCE_GFP(order > MAX_PAGE_ORDER, gfp))
		return NULL;

5) virtio_fs_enqueue_req() will retry the memory allocation in a
kworker, but it won't help, because kmalloc() will always return NULL
due to the abnormal size and finit_module() will hang forever.

A feasible solution is to limit the value of max_read for virtio-fs, so
the length passed to kmalloc() will be limited. However it will affect
the maximal read size for normal read. And for virtio-fs write initiated
from kernel, it has the similar problem but now there is no way to limit
fc->max_write in kernel.

So instead of limiting both the values of max_read and max_write in
kernel, introducing use_pages_for_kvec_io in fuse_conn and setting it as
true in virtiofs. When use_pages_for_kvec_io is enabled, fuse will use
pages instead of pointer to pass the KVEC_IO data.

After switching to pages for KVEC_IO data, these pages will be used for
DMA through virtio-fs. If these pages are backed by vmalloc(),
{flush|invalidate}_kernel_vmap_range() are necessary to flush or
invalidate the cache before the DMA operation. So add two new fields in
fuse_args_pages to record the base address of vmalloc area and the
condition indicating whether invalidation is needed. Perform the flush
in fuse_get_user_pages() for write operations and the invalidation in
fuse_release_user_pages() for read operations.

It may seem necessary to introduce another fie
---truncated---

## Which versions are affected by CVE-2024-53219?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-53219?

Apply the vendor's patch.

## Is CVE-2024-53219 being exploited?

There is no known exploitation of CVE-2024-53219 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-53219 and fix it if it is affected.

What it is: CVE-2024-53219 is a medium-severity denial of service vulnerability in Linux kernel, published on 27 Dec 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-53219 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2024-53219/ (Markdown: https://insights.sbomify.com/CVE-2024-53219/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-53219
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-53219
- OSV: https://osv.dev/vulnerability/CVE-2024-53219

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-53219/
Summaries are generated and may contain mistakes; the official description above is the record.