# CVE-2022-48821: misc: fastrpc: avoid double fput() on failed usercopy

> A use-after-free vulnerability in the Linux kernel's fastrpc driver allows local attackers to potentially execute code or escalate privileges via a failed usercopy operation.

- **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:** 16 Jul 2024
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2022-48821, GHSA-h4q9-9fhm-542g, UBUNTU-CVE-2022-48821

## What is CVE-2022-48821?

CVE-2022-48821 is a high-severity use after free vulnerability in Linux kernel, published on 16 Jul 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:

misc: fastrpc: avoid double fput() on failed usercopy

If the copy back to userland fails for the FASTRPC_IOCTL_ALLOC_DMA_BUFF
ioctl(), we shouldn't assume that 'buf->dmabuf' is still valid. In fact,
dma_buf_fd() called fd_install() before, i.e. "consumed" one reference,
leaving us with none.

Calling dma_buf_put() will therefore put a reference we no longer own,
leading to a valid file descritor table entry for an already released
'file' object which is a straight use-after-free.

Simply avoid calling dma_buf_put() and rely on the process exit code to
do the necessary cleanup, if needed, i.e. if the file descriptor is
still valid.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2022-48821?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-48821?

Apply the vendor's patch.

## Is CVE-2022-48821 being exploited?

There is no known exploitation of CVE-2022-48821 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-2022-48821 and fix it if it is affected.

What it is: CVE-2022-48821 is a high-severity use after free vulnerability in Linux kernel, published on 16 Jul 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-2022-48821 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-2022-48821/ (Markdown: https://insights.sbomify.com/CVE-2022-48821/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-48821
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-48821
- OSV: https://osv.dev/vulnerability/CVE-2022-48821

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-48821/
Summaries are generated and may contain mistakes; the official description above is the record.