# CVE-2023-53537: f2fs: fix to avoid use-after-free for cached IPU bio

> A use-after-free vulnerability in the Linux kernel's f2fs filesystem allows attackers to cause a system crash or potentially execute arbitrary code.

- **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:** 4 Oct 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2023-53537, DEBIAN-CVE-2023-53537, GHSA-f8rh-5cg2-mcj8, UBUNTU-CVE-2023-53537

## What is CVE-2023-53537?

CVE-2023-53537 is a high-severity use after free vulnerability in Linux kernel, published on 4 Oct 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:

f2fs: fix to avoid use-after-free for cached IPU bio

xfstest generic/019 reports a bug:

kernel BUG at mm/filemap.c:1619!
RIP: 0010:folio_end_writeback+0x8a/0x90
Call Trace:
 end_page_writeback+0x1c/0x60
 f2fs_write_end_io+0x199/0x420
 bio_endio+0x104/0x180
 submit_bio_noacct+0xa5/0x510
 submit_bio+0x48/0x80
 f2fs_submit_write_bio+0x35/0x300
 f2fs_submit_merged_ipu_write+0x2a0/0x2b0
 f2fs_write_single_data_page+0x838/0x8b0
 f2fs_write_cache_pages+0x379/0xa30
 f2fs_write_data_pages+0x30c/0x340
 do_writepages+0xd8/0x1b0
 __writeback_single_inode+0x44/0x370
 writeback_sb_inodes+0x233/0x4d0
 __writeback_inodes_wb+0x56/0xf0
 wb_writeback+0x1dd/0x2d0
 wb_workfn+0x367/0x4a0
 process_one_work+0x21d/0x430
 worker_thread+0x4e/0x3c0
 kthread+0x103/0x130
 ret_from_fork+0x2c/0x50

The root cause is: after cp_error is set, f2fs_submit_merged_ipu_write()
in f2fs_write_single_data_page() tries to flush IPU bio in cache, however
f2fs_submit_merged_ipu_write() missed to check validity of @bio parameter,
result in submitting random cached bio which belong to other IO context,
then it will cause use-after-free issue, fix it by adding additional
validity check.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2023-53537?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-53537?

Apply the vendor's patch.

## Is CVE-2023-53537 being exploited?

There is no known exploitation of CVE-2023-53537 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-2023-53537 and fix it if it is affected.

What it is: CVE-2023-53537 is a high-severity use after free vulnerability in Linux kernel, published on 4 Oct 2025. 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-2023-53537 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-2023-53537/ (Markdown: https://insights.sbomify.com/CVE-2023-53537/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53537
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53537
- OSV: https://osv.dev/vulnerability/CVE-2023-53537

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-53537/
Summaries are generated and may contain mistakes; the official description above is the record.