# CVE-2022-48988: memcg: fix possible use-after-free in memcg_write_event_control()

> A use-after-free vulnerability in the Linux kernel's memcg event control allows attackers to potentially execute code or escalate privileges via race conditions.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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:** 21 Oct 2024
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2022-48988, GHSA-9593-f5wq-r2vm, UBUNTU-CVE-2022-48988

## What is CVE-2022-48988?

CVE-2022-48988 is a high-severity use after free vulnerability in Linux kernel, published on 21 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:

memcg: fix possible use-after-free in memcg_write_event_control()

memcg_write_event_control() accesses the dentry->d_name of the specified
control fd to route the write call.  As a cgroup interface file can't be
renamed, it's safe to access d_name as long as the specified file is a
regular cgroup file.  Also, as these cgroup interface files can't be
removed before the directory, it's safe to access the parent too.

Prior to 347c4a874710 ("memcg: remove cgroup_event->cft"), there was a
call to __file_cft() which verified that the specified file is a regular
cgroupfs file before further accesses.  The cftype pointer returned from
__file_cft() was no longer necessary and the commit inadvertently dropped
the file type check with it allowing any file to slip through.  With the
invarients broken, the d_name and parent accesses can now race against
renames and removals of arbitrary files and cause use-after-free's.

Fix the bug by resurrecting the file type check in __file_cft().  Now that
cgroupfs is implemented through kernfs, checking the file operations needs
to go through a layer of indirection.  Instead, let's check the superblock
and dentry type.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2022-48988?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-48988?

Apply the vendor's patch.

## Is CVE-2022-48988 being exploited?

There is no known exploitation of CVE-2022-48988 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-2022-48988 and fix it if it is affected.

What it is: CVE-2022-48988 is a high-severity use after free vulnerability in Linux kernel, published on 21 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-2022-48988 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-2022-48988/ (Markdown: https://insights.sbomify.com/CVE-2022-48988/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-48988
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-48988
- OSV: https://osv.dev/vulnerability/CVE-2022-48988

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-48988/
Summaries are generated and may contain mistakes; the official description above is the record.