# CVE-2017-7539: Denial of service in Qemu

> A remote attacker can crash the QEMU NBD server by sending unexpected data during connection negotiation, causing a denial of service.

- **Severity:** Medium 5.3 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 Jul 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-8vvg-hj6f-q4wj, RHSA-2017:2628

## What is CVE-2017-7539?

CVE-2017-7539 is a medium-severity denial of service vulnerability in Qemu Qemu, published on 26 Jul 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An assertion-failure flaw was found in Qemu before 2.10.1, in the Network Block Device (NBD) server's initial connection negotiation, where the I/O coroutine was undefined. This could crash the qemu-nbd server if a client sent unexpected data during connection negotiation. A remote user or process could use this flaw to crash the qemu-nbd server resulting in denial of service.

Weakness: CWE-20 (Improper Input Validation), CWE-617 (Reachable Assertion)

## Which versions are affected by CVE-2017-7539?

It affects 3 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `qemu-img-rhev` | Red Hat:enterprise_linux:7::hypervisor | All versions | 10:2.9.0-16.el7_4.5 |
| `qemu-kvm-common-rhev` | Red Hat:enterprise_linux:7::hypervisor | All versions | 10:2.9.0-16.el7_4.5 |
| `qemu-kvm-rhev` | Red Hat:enterprise_linux:7::hypervisor | All versions | 10:2.9.0-16.el7_4.5 |
| `qemu-kvm-rhev-debuginfo` | Red Hat:enterprise_linux:7::hypervisor | All versions | 10:2.9.0-16.el7_4.5 |
| `qemu-kvm-tools-rhev` | Red Hat:enterprise_linux:7::hypervisor | All versions | 10:2.9.0-16.el7_4.5 |

Products: Qemu Qemu, Redhat Openstack, Redhat Virtualization.

## How do I fix CVE-2017-7539?

Upgrade to a fixed version.

## Is CVE-2017-7539 being exploited?

There is no known exploitation of CVE-2017-7539 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-2017-7539 and fix it if it is affected.

What it is: CVE-2017-7539 is a medium-severity denial of service vulnerability in Qemu Qemu, published on 26 Jul 2018. 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-2017-7539 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-2017-7539/ (Markdown: https://insights.sbomify.com/CVE-2017-7539/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-7539
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-7539
- OSV: https://osv.dev/vulnerability/CVE-2017-7539

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-7539/
Summaries are generated and may contain mistakes; the official description above is the record.