# CVE-2025-38677: f2fs: fix to avoid out-of-boundary access in dnode page

> A local attacker can trigger an out-of-bounds memory access in the f2fs filesystem, potentially causing a system crash or arbitrary code execution.

- **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:** 30 Aug 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-38677, DEBIAN-CVE-2025-38677, GHSA-p7jq-2wv5-rrmc, ROOT-OS-DEBIAN-11-CVE-2025-38677, ROOT-OS-DEBIAN-12-CVE-2025-38677, ROOT-OS-DEBIAN-13-CVE-2025-38677, ROOT-OS-UBUNTU-2204-CVE-2025-38677, ROOT-OS-UBUNTU-2404-CVE-2025-38677, UBUNTU-CVE-2025-38677

## What is CVE-2025-38677?

CVE-2025-38677 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 30 Aug 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 out-of-boundary access in dnode page

As Jiaming Zhang reported:

 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x1c1/0x2a0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x17e/0x800 mm/kasan/report.c:480
 kasan_report+0x147/0x180 mm/kasan/report.c:593
 data_blkaddr fs/f2fs/f2fs.h:3053 [inline]
 f2fs_data_blkaddr fs/f2fs/f2fs.h:3058 [inline]
 f2fs_get_dnode_of_data+0x1a09/0x1c40 fs/f2fs/node.c:855
 f2fs_reserve_block+0x53/0x310 fs/f2fs/data.c:1195
 prepare_write_begin fs/f2fs/data.c:3395 [inline]
 f2fs_write_begin+0xf39/0x2190 fs/f2fs/data.c:3594
 generic_perform_write+0x2c7/0x910 mm/filemap.c:4112
 f2fs_buffered_write_iter fs/f2fs/file.c:4988 [inline]
 f2fs_file_write_iter+0x1ec8/0x2410 fs/f2fs/file.c:5216
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x546/0xa90 fs/read_write.c:686
 ksys_write+0x149/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x3d0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The root cause is in the corrupted image, there is a dnode has the same
node id w/ its inode, so during f2fs_get_dnode_of_data(), it tries to
access block address in dnode at offset 934, however it parses the dnode
as inode node, so that get_dnode_addr() returns 360, then it tries to
access page address from 360 + 934 * 4 = 4096 w/ 4 bytes.

To fix this issue, let's add sanity check for node id of all direct nodes
during f2fs_get_dnode_of_data().

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2025-38677?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-38677?

Apply the vendor's patch.

## Is CVE-2025-38677 being exploited?

There is no known exploitation of CVE-2025-38677 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-38677 and fix it if it is affected.

What it is: CVE-2025-38677 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 30 Aug 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-2025-38677 in the wild and no public exploit code.

Affected product: Debian Debian Linux. 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-2025-38677/ (Markdown: https://insights.sbomify.com/CVE-2025-38677/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38677
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38677
- OSV: https://osv.dev/vulnerability/CVE-2025-38677

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38677/
Summaries are generated and may contain mistakes; the official description above is the record.