# CVE-2024-57952: Revert "libfs: fix infinite directory reads for offset dir"

> A logic error in the Linux kernel directory offset allocator causes directory entries to become permanently invisible on 32-bit systems after counter wrap.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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:** 12 Feb 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2024-57952, DEBIAN-CVE-2024-57952, GHSA-qxjr-36pm-q2q2, ROOT-OS-DEBIAN-11-CVE-2024-57952, ROOT-OS-DEBIAN-12-CVE-2024-57952, ROOT-OS-UBUNTU-2204-CVE-2024-57952, UBUNTU-CVE-2024-57952

## What is CVE-2024-57952?

CVE-2024-57952 is a high-severity denial of service vulnerability in Linux kernel, published on 12 Feb 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:

Revert "libfs: fix infinite directory reads for offset dir"

The current directory offset allocator (based on mtree_alloc_cyclic)
stores the next offset value to return in octx->next_offset. This
mechanism typically returns values that increase monotonically over
time. Eventually, though, the newly allocated offset value wraps
back to a low number (say, 2) which is smaller than other already-
allocated offset values.

Yu Kuai <yukuai3@huawei.com> reports that, after commit 64a7ce76fb90
("libfs: fix infinite directory reads for offset dir"), if a
directory's offset allocator wraps, existing entries are no longer
visible via readdir/getdents because offset_readdir() stops listing
entries once an entry's offset is larger than octx->next_offset.
These entries vanish persistently -- they can be looked up, but will
never again appear in readdir(3) output.

The reason for this is that the commit treats directory offsets as
monotonically increasing integer values rather than opaque cookies,
and introduces this comparison:

	if (dentry2offset(dentry) >= last_index) {

On 64-bit platforms, the directory offset value upper bound is
2^63 - 1. Directory offsets will monotonically increase for millions
of years without wrapping.

On 32-bit platforms, however, LONG_MAX is 2^31 - 1. The allocator
can wrap after only a few weeks (at worst).

Revert commit 64a7ce76fb90 ("libfs: fix infinite directory reads for
offset dir") to prepare for a fix that can work properly on 32-bit
systems and might apply to recent LTS kernels where shmem employs
the simple_offset mechanism.

## Which versions are affected by CVE-2024-57952?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-57952?

Apply the vendor's patch.

## Is CVE-2024-57952 being exploited?

There is no known exploitation of CVE-2024-57952 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-2024-57952 and fix it if it is affected.

What it is: CVE-2024-57952 is a high-severity denial of service vulnerability in Linux kernel, published on 12 Feb 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-2024-57952 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-2024-57952/ (Markdown: https://insights.sbomify.com/CVE-2024-57952/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-57952
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-57952
- OSV: https://osv.dev/vulnerability/CVE-2024-57952

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-57952/
Summaries are generated and may contain mistakes; the official description above is the record.