# CVE-2021-47278: bus: mhi: pci_generic: Fix possible use-after-free in mhi_pci_remove()

> A use-after-free vulnerability in the Linux kernel MHI PCI driver allows attackers to cause denial of service or execute arbitrary code.

- **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:** No
- **Published:** 21 May 2024
- **Updated:** 11 May 2026
- **Also known as:** GHSA-5j57-53hq-vmc7, UBUNTU-CVE-2021-47278

## What is CVE-2021-47278?

CVE-2021-47278 is a high-severity use after free vulnerability in Linux kernel, published on 21 May 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:

bus: mhi: pci_generic: Fix possible use-after-free in mhi_pci_remove()

This driver's remove path calls del_timer(). However, that function
does not wait until the timer handler finishes. This means that the
timer handler may still be running after the driver's remove function
has finished, which would result in a use-after-free.

Fix by calling del_timer_sync(), which makes sure the timer handler
has finished, and unable to re-schedule itself.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2021-47278?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-47278?

No fix has been published for CVE-2021-47278 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-47278 being exploited?

There is no known exploitation of CVE-2021-47278 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-2021-47278 and fix it if it is affected.

What it is: CVE-2021-47278 is a high-severity use after free vulnerability in Linux kernel, published on 21 May 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-2021-47278 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-2021-47278/ (Markdown: https://insights.sbomify.com/CVE-2021-47278/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47278
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47278
- OSV: https://osv.dev/vulnerability/CVE-2021-47278

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47278/
Summaries are generated and may contain mistakes; the official description above is the record.