# CVE-2023-53564: ocfs2: fix defrag path triggering jbd2 ASSERT

> A flaw in the OCFS2 filesystem's defragmentation path triggers a kernel assertion failure, causing a system crash and 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 Oct 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-53564, DEBIAN-CVE-2023-53564, GHSA-3pwq-c4jq-fp68, UBUNTU-CVE-2023-53564

## What is CVE-2023-53564?

CVE-2023-53564 is a medium-severity denial of service 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:

ocfs2: fix defrag path triggering jbd2 ASSERT

code path:

ocfs2_ioctl_move_extents
 ocfs2_move_extents
  ocfs2_defrag_extent
   __ocfs2_move_extent
    + ocfs2_journal_access_di
    + ocfs2_split_extent  //sub-paths call jbd2_journal_restart
    + ocfs2_journal_dirty //crash by jbs2 ASSERT

crash stacks:

PID: 11297  TASK: ffff974a676dcd00  CPU: 67  COMMAND: "defragfs.ocfs2"
 #0 [ffffb25d8dad3900] machine_kexec at ffffffff8386fe01
 #1 [ffffb25d8dad3958] __crash_kexec at ffffffff8395959d
 #2 [ffffb25d8dad3a20] crash_kexec at ffffffff8395a45d
 #3 [ffffb25d8dad3a38] oops_end at ffffffff83836d3f
 #4 [ffffb25d8dad3a58] do_trap at ffffffff83833205
 #5 [ffffb25d8dad3aa0] do_invalid_op at ffffffff83833aa6
 #6 [ffffb25d8dad3ac0] invalid_op at ffffffff84200d18
    [exception RIP: jbd2_journal_dirty_metadata+0x2ba]
    RIP: ffffffffc09ca54a  RSP: ffffb25d8dad3b70  RFLAGS: 00010207
    RAX: 0000000000000000  RBX: ffff9706eedc5248  RCX: 0000000000000000
    RDX: 0000000000000001  RSI: ffff97337029ea28  RDI: ffff9706eedc5250
    RBP: ffff9703c3520200   R8: 000000000f46b0b2   R9: 0000000000000000
    R10: 0000000000000001  R11: 00000001000000fe  R12: ffff97337029ea28
    R13: 0000000000000000  R14: ffff9703de59bf60  R15: ffff9706eedc5250
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #7 [ffffb25d8dad3ba8] ocfs2_journal_dirty at ffffffffc137fb95 [ocfs2]
 #8 [ffffb25d8dad3be8] __ocfs2_move_extent at ffffffffc139a950 [ocfs2]
 #9 [ffffb25d8dad3c80] ocfs2_defrag_extent at ffffffffc139b2d2 [ocfs2]

Analysis

This bug has the same root cause of 'commit 7f27ec978b0e ("ocfs2: call
ocfs2_journal_access_di() before ocfs2_journal_dirty() in
ocfs2_write_end_nolock()")'.  For this bug, jbd2_journal_restart() is
called by ocfs2_split_extent() during defragmenting.

How to fix

For ocfs2_split_extent() can handle journal operations totally by itself. 
Caller doesn't need to call journal access/dirty pair, and caller only
needs to call journal start/stop pair.  The fix method is to remove
journal access/dirty from __ocfs2_move_extent().

The discussion for this patch:
https://oss.oracle.com/pipermail/ocfs2-devel/2023-February/000647.html

Weakness: CWE-617 (Reachable Assertion)

## Which versions are affected by CVE-2023-53564?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-53564?

Apply the vendor's patch.

## Is CVE-2023-53564 being exploited?

There is no known exploitation of CVE-2023-53564 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-2023-53564 and fix it if it is affected.

What it is: CVE-2023-53564 is a medium-severity denial of service 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-2023-53564 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-2023-53564/ (Markdown: https://insights.sbomify.com/CVE-2023-53564/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53564
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53564
- OSV: https://osv.dev/vulnerability/CVE-2023-53564

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-53564/
Summaries are generated and may contain mistakes; the official description above is the record.