# CVE-2024-47660: fsnotify: clear PARENT_WATCHED flags lazily

> A race condition in the Linux kernel fsnotify subsystem can cause softlockups and denial of service when removing watches from directories with many dentries.

- **Severity:** Medium 4.7 (`CVSS:3.1/AV:L/AC:H/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:** 9 Oct 2024
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2024-47660, DEBIAN-CVE-2024-47660, GHSA-ccgr-xwcc-r26p, ROOT-OS-DEBIAN-11-CVE-2024-47660, UBUNTU-CVE-2024-47660

## What is CVE-2024-47660?

CVE-2024-47660 is a medium-severity vulnerability in Linux kernel, published on 9 Oct 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:

fsnotify: clear PARENT_WATCHED flags lazily

In some setups directories can have many (usually negative) dentries.
Hence __fsnotify_update_child_dentry_flags() function can take a
significant amount of time. Since the bulk of this function happens
under inode->i_lock this causes a significant contention on the lock
when we remove the watch from the directory as the
__fsnotify_update_child_dentry_flags() call from fsnotify_recalc_mask()
races with __fsnotify_update_child_dentry_flags() calls from
__fsnotify_parent() happening on children. This can lead upto softlockup
reports reported by users.

Fix the problem by calling fsnotify_update_children_dentry_flags() to
set PARENT_WATCHED flags only when parent starts watching children.

When parent stops watching children, clear false positive PARENT_WATCHED
flags lazily in __fsnotify_parent() for each accessed child.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2024-47660?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-47660?

Apply the vendor's patch.

## Is CVE-2024-47660 being exploited?

There is no known exploitation of CVE-2024-47660 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-2024-47660 and fix it if it is affected.

What it is: CVE-2024-47660 is a medium-severity vulnerability in Linux kernel, published on 9 Oct 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-2024-47660 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-2024-47660/ (Markdown: https://insights.sbomify.com/CVE-2024-47660/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-47660
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-47660
- OSV: https://osv.dev/vulnerability/CVE-2024-47660

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-47660/
Summaries are generated and may contain mistakes; the official description above is the record.