# CVE-2026-40215: Use after free in OpenVPN

> Remote attackers can crash the OpenVPN server or leak heap memory via a race condition during TLS session promotion.

- **Severity:** Medium 6.1 (`CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:N/VA:H/SC:L/SI:N/SA:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 Jun 2026
- **Updated:** 16 Jun 2026
- **Also known as:** ALPINE-CVE-2026-40215, DEBIAN-CVE-2026-40215, GHSA-3mmv-h5fc-pvwj, OESA-2026-2625, UBUNTU-CVE-2026-40215

## What is CVE-2026-40215?

CVE-2026-40215 is a medium-severity use after free vulnerability in OpenVPN, published on 8 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A race condition in OpenVPN 2.6.0 through 2.6.19 and 2.7_alpha1 through 2.7.1 allows remote attackers to potentially cause a server crash or leak heap memory via a use-after-free triggered during TLS session promotion.

Weakness: CWE-416 (Use After Free), CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-40215?

It affects 1 product.


Products: Openvpn Openvpn.

## How do I fix CVE-2026-40215?

Upgrade to a fixed version.

## Is CVE-2026-40215 being exploited?

There is no known exploitation of CVE-2026-40215 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-2026-40215 and fix it if it is affected.

What it is: CVE-2026-40215 is a medium-severity use after free vulnerability in OpenVPN, published on 8 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-40215 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-2026-40215/ (Markdown: https://insights.sbomify.com/CVE-2026-40215/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-40215
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-40215
- OSV: https://osv.dev/vulnerability/CVE-2026-40215

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-40215/
Summaries are generated and may contain mistakes; the official description above is the record.