# CVE-2022-49349: ext4: fix use-after-free in ext4_rename_dir_prepare

> A use-after-free vulnerability in the Linux kernel's ext4 filesystem allows local attackers to cause a denial of service or potentially execute arbitrary code.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 26 Feb 2025
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2022-49349, GHSA-qwcq-8262-9j44, UBUNTU-CVE-2022-49349

## What is CVE-2022-49349?

CVE-2022-49349 is a high-severity use after free vulnerability in Linux kernel, published on 26 Feb 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

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

ext4: fix use-after-free in ext4_rename_dir_prepare

We got issue as follows:
EXT4-fs (loop0): mounted filesystem without journal. Opts: ,errors=continue
ext4_get_first_dir_block: bh->b_data=0xffff88810bee6000 len=34478
ext4_get_first_dir_block: *parent_de=0xffff88810beee6ae bh->b_data=0xffff88810bee6000
ext4_rename_dir_prepare: [1] parent_de=0xffff88810beee6ae
==================================================================
BUG: KASAN: use-after-free in ext4_rename_dir_prepare+0x152/0x220
Read of size 4 at addr ffff88810beee6ae by task rep/1895

CPU: 13 PID: 1895 Comm: rep Not tainted 5.10.0+ #241
Call Trace:
 dump_stack+0xbe/0xf9
 print_address_description.constprop.0+0x1e/0x220
 kasan_report.cold+0x37/0x7f
 ext4_rename_dir_prepare+0x152/0x220
 ext4_rename+0xf44/0x1ad0
 ext4_rename2+0x11c/0x170
 vfs_rename+0xa84/0x1440
 do_renameat2+0x683/0x8f0
 __x64_sys_renameat+0x53/0x60
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f45a6fc41c9
RSP: 002b:00007ffc5a470218 EFLAGS: 00000246 ORIG_RAX: 0000000000000108
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f45a6fc41c9
RDX: 0000000000000005 RSI: 0000000020000180 RDI: 0000000000000005
RBP: 00007ffc5a470240 R08: 00007ffc5a470160 R09: 0000000020000080
R10: 00000000200001c0 R11: 0000000000000246 R12: 0000000000400bb0
R13: 00007ffc5a470320 R14: 0000000000000000 R15: 0000000000000000

The buggy address belongs to the page:
page:00000000440015ce refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x10beee
flags: 0x200000000000000()
raw: 0200000000000000 ffffea00043ff4c8 ffffea0004325608 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88810beee580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88810beee600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88810beee680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                  ^
 ffff88810beee700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88810beee780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
Disabling lock debugging due to kernel taint
ext4_rename_dir_prepare: [2] parent_de->inode=3537895424
ext4_rename_dir_prepare: [3] dir=0xffff888124170140
ext4_rename_dir_prepare: [4] ino=2
ext4_rename_dir_prepare: ent->dir->i_ino=2 parent=-757071872

Reason is first directory entry which 'rec_len' is 34478, then will get illegal
parent entry. Now, we do not check directory entry after read directory block
in 'ext4_get_first_dir_block'.
To solve this issue, check directory entry in 'ext4_get_first_dir_block'.

[ Trigger an ext4_error() instead of just warning if the directory is
  missing a '.' or '..' entry.   Also make sure we return an error code
  if the file system is corrupted.  -TYT ]

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2022-49349?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-49349?

Apply the vendor's patch.

## Is CVE-2022-49349 being exploited?

There is no known exploitation of CVE-2022-49349 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-2022-49349 and fix it if it is affected.

What it is: CVE-2022-49349 is a high-severity use after free vulnerability in Linux kernel, published on 26 Feb 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2022-49349 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-2022-49349/ (Markdown: https://insights.sbomify.com/CVE-2022-49349/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-49349
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-49349
- OSV: https://osv.dev/vulnerability/CVE-2022-49349

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-49349/
Summaries are generated and may contain mistakes; the official description above is the record.