# CVE-2019-20175: Denial of service in n/a

> A privileged guest user can crash the QEMU host process via a specific SCSI command, causing a denial of service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 31 Dec 2019
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2019-20175, GHSA-4r96-hw22-hhc7

## What is CVE-2019-20175?

CVE-2019-20175 is a high-severity denial of service vulnerability in Qemu Qemu, published on 31 Dec 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in ide_dma_cb() in hw/ide/core.c in QEMU 2.4.0 through 4.2.0. The guest system can crash the QEMU process in the host system via a special SCSI_IOCTL_SEND_COMMAND. It hits an assertion that implies that the size of successful DMA transfers there must be a multiple of 512 (the size of a sector). NOTE: a member of the QEMU security team disputes the significance of this issue because a "privileged guest user has many ways to cause similar DoS effect, without triggering this assert.

Weakness: CWE-754 (Improper Check for Unusual or Exceptional Conditions)

## Which versions are affected by CVE-2019-20175?

It affects 1 product.


Products: Qemu Qemu.

## How do I fix CVE-2019-20175?

Apply the vendor's patch.

## Is CVE-2019-20175 being exploited?

There is no known exploitation of CVE-2019-20175 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-2019-20175 and fix it if it is affected.

What it is: CVE-2019-20175 is a high-severity denial of service vulnerability in Qemu Qemu, published on 31 Dec 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2019-20175 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-2019-20175/ (Markdown: https://insights.sbomify.com/CVE-2019-20175/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-20175
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-20175
- OSV: https://osv.dev/vulnerability/CVE-2019-20175

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-20175/
Summaries are generated and may contain mistakes; the official description above is the record.