# CVE-2024-46701: libfs: fix infinite directory reads for offset dir

> A flaw in the Linux kernel's tmpfs implementation allows attackers to cause an infinite loop during directory reads, leading to 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:** 13 Sep 2024
- **Updated:** 11 May 2026
- **Also known as:** AZL-49318, BELL-CVE-2024-46701, DEBIAN-CVE-2024-46701, GHSA-q844-wpfg-w2h9, UBUNTU-CVE-2024-46701

## What is CVE-2024-46701?

CVE-2024-46701 is a medium-severity denial of service vulnerability in Linux kernel, published on 13 Sep 2024. 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:

libfs: fix infinite directory reads for offset dir

After we switch tmpfs dir operations from simple_dir_operations to
simple_offset_dir_operations, every rename happened will fill new dentry
to dest dir's maple tree(&SHMEM_I(inode)->dir_offsets->mt) with a free
key starting with octx->newx_offset, and then set newx_offset equals to
free key + 1. This will lead to infinite readdir combine with rename
happened at the same time, which fail generic/736 in xfstests(detail show
as below).

1. create 5000 files(1 2 3...) under one dir
2. call readdir(man 3 readdir) once, and get one entry
3. rename(entry, "TEMPFILE"), then rename("TEMPFILE", entry)
4. loop 2~3, until readdir return nothing or we loop too many
   times(tmpfs break test with the second condition)

We choose the same logic what commit 9b378f6ad48cf ("btrfs: fix infinite
directory reads") to fix it, record the last_index when we open dir, and
do not emit the entry which index >= last_index. The file->private_data
now used in offset dir can use directly to do this, and we also update
the last_index when we llseek the dir file.

[brauner: only update last_index after seek when offset is zero like Jan suggested]

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2024-46701?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-46701?

Apply the vendor's patch.

## Is CVE-2024-46701 being exploited?

There is no known exploitation of CVE-2024-46701 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-2024-46701 and fix it if it is affected.

What it is: CVE-2024-46701 is a medium-severity denial of service vulnerability in Linux kernel, published on 13 Sep 2024. 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-2024-46701 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-2024-46701/ (Markdown: https://insights.sbomify.com/CVE-2024-46701/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-46701
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-46701
- OSV: https://osv.dev/vulnerability/CVE-2024-46701

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-46701/
Summaries are generated and may contain mistakes; the official description above is the record.