# CVE-2011-1751: Use after free in n/a

> Privileged guest users can trigger a use-after-free in QEMU's PIIX4 emulation to crash the guest or execute arbitrary code.

- **Severity:** High 7.4 (`AV:A/AC:M/Au:S/C:C/I:C/A:C`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 Jun 2012
- **Updated:** 6 Aug 2024
- **Also known as:** DSA-2241-1, GHSA-5x39-mv3c-q6cc

## What is CVE-2011-1751?

CVE-2011-1751 is a high-severity use after free vulnerability in Qemu Qemu, published on 21 Jun 2012. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The pciej_write function in hw/acpi_piix4.c in the PIIX4 Power Management emulation in qemu-kvm does not check if a device is hotpluggable before unplugging the PCI-ISA bridge, which allows privileged guest users to cause a denial of service (guest crash) and possibly execute arbitrary code by sending a crafted value to the 0xae08 (PCI_EJ_BASE) I/O port, which leads to a use-after-free related to "active qemu timers."

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2011-1751?

It affects 1 product.


Products: Qemu Qemu.

## How do I fix CVE-2011-1751?

Apply the vendor's patch.

## Is CVE-2011-1751 being exploited?

There is no known exploitation of CVE-2011-1751 in the wild and no public exploit code.

## Other vulnerabilities in Qemu Qemu

- [CVE-2022-36648](https://insights.sbomify.com/CVE-2022-36648/): Null dereference in n/a (critical 10.0)
- [CVE-2015-8556](https://insights.sbomify.com/CVE-2015-8556/): Race condition in n/a (critical 10.0)
- [CVE-2009-3616](https://insights.sbomify.com/CVE-2009-3616/): Use after free in n/a (critical 9.9)
- [CVE-2019-12928](https://insights.sbomify.com/CVE-2019-12928/): Command injection in n/a (critical 9.8)
- [CVE-2019-12929](https://insights.sbomify.com/CVE-2019-12929/): Command injection in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2011-1751 and fix it if it is affected.

What it is: CVE-2011-1751 is a high-severity use after free vulnerability in Qemu Qemu, published on 21 Jun 2012. 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-2011-1751 in the wild and no public exploit code.

Affected product: Qemu Qemu. 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-2011-1751/ (Markdown: https://insights.sbomify.com/CVE-2011-1751/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2011-1751
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2011-1751
- OSV: https://osv.dev/vulnerability/CVE-2011-1751

---
From sbomify Insights: https://insights.sbomify.com/CVE-2011-1751/
Summaries are generated and may contain mistakes; the official description above is the record.