# CVE-2025-68337: jbd2: avoid bug_on in jbd2_journal_get_create_access() when file system corrupted

> A local attacker can trigger a kernel crash via a corrupted ext4 filesystem image, causing a denial of service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 22 Dec 2025
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-72874, BELL-CVE-2025-68337, DEBIAN-CVE-2025-68337, GHSA-75fx-9v9v-4p3x, ROOT-OS-DEBIAN-11-CVE-2025-68337, ROOT-OS-DEBIAN-12-CVE-2025-68337, ROOT-OS-UBUNTU-2204-CVE-2025-68337, ROOT-OS-UBUNTU-2404-CVE-2025-68337, UBUNTU-CVE-2025-68337

## What is CVE-2025-68337?

CVE-2025-68337 is a high-severity denial of service vulnerability in Linux, published on 22 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

jbd2: avoid bug_on in jbd2_journal_get_create_access() when file system corrupted

There's issue when file system corrupted:
------------[ cut here ]------------
kernel BUG at fs/jbd2/transaction.c:1289!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 5 UID: 0 PID: 2031 Comm: mkdir Not tainted 6.18.0-rc1-next
RIP: 0010:jbd2_journal_get_create_access+0x3b6/0x4d0
RSP: 0018:ffff888117aafa30 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffff88811a86b000 RCX: ffffffff89a63534
RDX: 1ffff110200ec602 RSI: 0000000000000004 RDI: ffff888100763010
RBP: ffff888100763000 R08: 0000000000000001 R09: ffff888100763028
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000
R13: ffff88812c432000 R14: ffff88812c608000 R15: ffff888120bfc000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f91d6970c99 CR3: 00000001159c4000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __ext4_journal_get_create_access+0x42/0x170
 ext4_getblk+0x319/0x6f0
 ext4_bread+0x11/0x100
 ext4_append+0x1e6/0x4a0
 ext4_init_new_dir+0x145/0x1d0
 ext4_mkdir+0x326/0x920
 vfs_mkdir+0x45c/0x740
 do_mkdirat+0x234/0x2f0
 __x64_sys_mkdir+0xd6/0x120
 do_syscall_64+0x5f/0xfa0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

The above issue occurs with us in errors=continue mode when accompanied by
storage failures. There have been many inconsistencies in the file system
data.
In the case of file system data inconsistency, for example, if the block
bitmap of a referenced block is not set, it can lead to the situation where
a block being committed is allocated and used again. As a result, the
following condition will not be satisfied then trigger BUG_ON. Of course,
it is entirely possible to construct a problematic image that can trigger
this BUG_ON through specific operations. In fact, I have constructed such
an image and easily reproduced this issue.
Therefore, J_ASSERT() holds true only under ideal conditions, but it may
not necessarily be satisfied in exceptional scenarios. Using J_ASSERT()
directly in abnormal situations would cause the system to crash, which is
clearly not what we want. So here we directly trigger a JBD abort instead
of immediately invoking BUG_ON.

## Which versions are affected by CVE-2025-68337?


## How do I fix CVE-2025-68337?

Apply the vendor's patch.

## Is CVE-2025-68337 being exploited?

There is no known exploitation of CVE-2025-68337 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68337 and fix it if it is affected.

What it is: CVE-2025-68337 is a high-severity denial of service vulnerability in Linux, published on 22 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-68337 in the wild and no public exploit code.

Affected product: 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-2025-68337/ (Markdown: https://insights.sbomify.com/CVE-2025-68337/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68337
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68337
- OSV: https://osv.dev/vulnerability/CVE-2025-68337

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68337/
Summaries are generated and may contain mistakes; the official description above is the record.