# CVE-2017-7520: Denial of service in OpenVPN

> A man-in-the-middle attacker can cause denial of service or leak sensitive memory in OpenVPN servers.

- **Severity:** High 7.4 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/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:** 27 Jun 2017
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2017-7520, DLA-999-1, GHSA-757r-jmm6-p24p, UBUNTU-CVE-2017-7520

## What is CVE-2017-7520?

CVE-2017-7520 is a high-severity denial of service vulnerability in OpenVPN, published on 27 Jun 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

OpenVPN versions before 2.4.3 and before 2.3.17 are vulnerable to denial-of-service and/or possibly sensitive memory leak triggered by man-in-the-middle attacker.

Weakness: CWE-125 (Out-of-bounds Read), CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2017-7520?

It affects 1 product.


Products: Openvpn Openvpn.

## How do I fix CVE-2017-7520?

Upgrade to a fixed version.

## Is CVE-2017-7520 being exploited?

There is no known exploitation of CVE-2017-7520 in the wild and no public exploit code.

## Other vulnerabilities in OpenVPN

- [CVE-2025-12106](https://insights.sbomify.com/CVE-2025-12106/): Memory corruption in OpenVPN (critical 9.1)
- [CVE-2024-5594](https://insights.sbomify.com/CVE-2024-5594/): Information disclosure in OpenVPN (critical 9.1)
- [CVE-2018-7544](https://insights.sbomify.com/CVE-2018-7544/): Cross-site request forgery in n/a (critical 9.1)
- [CVE-2006-1629](https://insights.sbomify.com/CVE-2006-1629/): Code injection in n/a (critical 9.0)
- [CVE-2024-4877](https://insights.sbomify.com/CVE-2024-4877/): Privilege escalation in OpenVPN (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-7520 and fix it if it is affected.

What it is: CVE-2017-7520 is a high-severity denial of service vulnerability in OpenVPN, published on 27 Jun 2017. 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-2017-7520 in the wild and no public exploit code.

Affected product: OpenVPN. 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-2017-7520/ (Markdown: https://insights.sbomify.com/CVE-2017-7520/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-7520
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-7520
- OSV: https://osv.dev/vulnerability/CVE-2017-7520

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-7520/
Summaries are generated and may contain mistakes; the official description above is the record.