# CVE-2026-23224: erofs: fix UAF issue for file-backed mounts w/ directio option

> A use-after-free vulnerability in the Linux kernel EROFS filesystem allows local attackers to cause a system crash or potentially execute code when using file-backed mounts with the directio option.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 18 Feb 2026
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2026-23224, DEBIAN-CVE-2026-23224, GHSA-8j5g-3q2r-xfjh, ROOT-OS-DEBIAN-11-CVE-2026-23224, ROOT-OS-DEBIAN-12-CVE-2026-23224, UBUNTU-CVE-2026-23224

## What is CVE-2026-23224?

CVE-2026-23224 is a high-severity use after free vulnerability in Linux kernel, published on 18 Feb 2026. 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:

erofs: fix UAF issue for file-backed mounts w/ directio option

[    9.269940][ T3222] Call trace:
[    9.269948][ T3222]  ext4_file_read_iter+0xac/0x108
[    9.269979][ T3222]  vfs_iocb_iter_read+0xac/0x198
[    9.269993][ T3222]  erofs_fileio_rq_submit+0x12c/0x180
[    9.270008][ T3222]  erofs_fileio_submit_bio+0x14/0x24
[    9.270030][ T3222]  z_erofs_runqueue+0x834/0x8ac
[    9.270054][ T3222]  z_erofs_read_folio+0x120/0x220
[    9.270083][ T3222]  filemap_read_folio+0x60/0x120
[    9.270102][ T3222]  filemap_fault+0xcac/0x1060
[    9.270119][ T3222]  do_pte_missing+0x2d8/0x1554
[    9.270131][ T3222]  handle_mm_fault+0x5ec/0x70c
[    9.270142][ T3222]  do_page_fault+0x178/0x88c
[    9.270167][ T3222]  do_translation_fault+0x38/0x54
[    9.270183][ T3222]  do_mem_abort+0x54/0xac
[    9.270208][ T3222]  el0_da+0x44/0x7c
[    9.270227][ T3222]  el0t_64_sync_handler+0x5c/0xf4
[    9.270253][ T3222]  el0t_64_sync+0x1bc/0x1c0

EROFS may encounter above panic when enabling file-backed mount w/
directio mount option, the root cause is it may suffer UAF in below
race condition:

- z_erofs_read_folio                          wq s_dio_done_wq
 - z_erofs_runqueue
  - erofs_fileio_submit_bio
   - erofs_fileio_rq_submit
    - vfs_iocb_iter_read
     - ext4_file_read_iter
      - ext4_dio_read_iter
       - iomap_dio_rw
       : bio was submitted and return -EIOCBQUEUED
                                              - dio_aio_complete_work
                                               - dio_complete
                                                - dio->iocb->ki_complete (erofs_fileio_ki_complete())
                                                 - kfree(rq)
                                                 : it frees iocb, iocb.ki_filp can be UAF in file_accessed().
       - file_accessed
       : access NULL file point

Introduce a reference count in struct erofs_fileio_rq, and initialize it
as two, both erofs_fileio_ki_complete() and erofs_fileio_rq_submit() will
decrease reference count, the last one decreasing the reference count
to zero will free rq.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-23224?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23224?

Apply the vendor's patch.

## Is CVE-2026-23224 being exploited?

There is no known exploitation of CVE-2026-23224 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-2026-23224 and fix it if it is affected.

What it is: CVE-2026-23224 is a high-severity use after free vulnerability in Linux kernel, published on 18 Feb 2026. 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-2026-23224 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-2026-23224/ (Markdown: https://insights.sbomify.com/CVE-2026-23224/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23224
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23224
- OSV: https://osv.dev/vulnerability/CVE-2026-23224

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23224/
Summaries are generated and may contain mistakes; the official description above is the record.