# CVE-2025-38220: ext4: only dirty folios when data journaling regular files

> A local attacker can trigger a kernel crash via a crafted symlink in the ext4 orphan list, causing a denial of service.

- **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:** 4 Jul 2025
- **Updated:** 11 May 2026
- **Also known as:** AZL-64767, BELL-CVE-2025-38220, DEBIAN-CVE-2025-38220, GHSA-m9fq-g2m8-9p75, ROOT-OS-UBUNTU-2404-CVE-2025-38220, UBUNTU-CVE-2025-38220

## What is CVE-2025-38220?

CVE-2025-38220 is a medium-severity vulnerability in Linux kernel, published on 4 Jul 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:

ext4: only dirty folios when data journaling regular files

fstest generic/388 occasionally reproduces a crash that looks as
follows:

BUG: kernel NULL pointer dereference, address: 0000000000000000
...
Call Trace:
 <TASK>
 ext4_block_zero_page_range+0x30c/0x380 [ext4]
 ext4_truncate+0x436/0x440 [ext4]
 ext4_process_orphan+0x5d/0x110 [ext4]
 ext4_orphan_cleanup+0x124/0x4f0 [ext4]
 ext4_fill_super+0x262d/0x3110 [ext4]
 get_tree_bdev_flags+0x132/0x1d0
 vfs_get_tree+0x26/0xd0
 vfs_cmd_create+0x59/0xe0
 __do_sys_fsconfig+0x4ed/0x6b0
 do_syscall_64+0x82/0x170
 ...

This occurs when processing a symlink inode from the orphan list. The
partial block zeroing code in the truncate path calls
ext4_dirty_journalled_data() -> folio_mark_dirty(). The latter calls
mapping->a_ops->dirty_folio(), but symlink inodes are not assigned an
a_ops vector in ext4, hence the crash.

To avoid this problem, update the ext4_dirty_journalled_data() helper to
only mark the folio dirty on regular files (for which a_ops is
assigned). This also matches the journaling logic in the ext4_symlink()
creation path, where ext4_handle_dirty_metadata() is called directly.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2025-38220?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-38220?

Apply the vendor's patch.

## Is CVE-2025-38220 being exploited?

There is no known exploitation of CVE-2025-38220 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-2025-38220 and fix it if it is affected.

What it is: CVE-2025-38220 is a medium-severity vulnerability in Linux kernel, published on 4 Jul 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-2025-38220 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-2025-38220/ (Markdown: https://insights.sbomify.com/CVE-2025-38220/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38220
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38220
- OSV: https://osv.dev/vulnerability/CVE-2025-38220

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38220/
Summaries are generated and may contain mistakes; the official description above is the record.