# CVE-2023-27395: Memory corruption in SoftEther VPN

> A heap-based buffer overflow in SoftEther VPN allows arbitrary code execution via a crafted packet during a man-in-the-middle attack.

- **Severity:** Critical 9.0 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Oct 2023
- **Updated:** 2 Aug 2024
- **Also known as:** GHSA-33mh-qwc8-jxxx

## What is CVE-2023-27395?

CVE-2023-27395 is a critical memory corruption vulnerability in SoftEther VPN, published on 12 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A heap-based buffer overflow vulnerability exists in the vpnserver WpcParsePacket() functionality of SoftEther VPN 4.41-9782-beta, 5.01.9674 and 5.02. A specially crafted network packet can lead to arbitrary code execution. An attacker can perform a man-in-the-middle attack to trigger this vulnerability.

Weakness: CWE-787 (Out-of-bounds Write), CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2023-27395?

It affects 1 product.


Products: Softether Vpn.

## How do I fix CVE-2023-27395?

No fix has been published for CVE-2023-27395 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-27395 being exploited?

There is no known exploitation of CVE-2023-27395 in the wild and no public exploit code.

## Other vulnerabilities in SoftEther VPN

- [CVE-2025-25565](https://insights.sbomify.com/CVE-2025-25565/): Memory corruption in n/a (critical 9.8)
- [CVE-2025-25567](https://insights.sbomify.com/CVE-2025-25567/): Memory corruption in n/a (critical 9.8)
- [CVE-2025-25568](https://insights.sbomify.com/CVE-2025-25568/): Use after free in n/a (critical 9.8)
- [CVE-2023-32634](https://insights.sbomify.com/CVE-2023-32634/): Auth bypass in SoftEther VPN (high 7.8)
- [CVE-2023-22308](https://insights.sbomify.com/CVE-2023-22308/): Integer overflow in SoftEther VPN (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-27395 and fix it if it is affected.

What it is: CVE-2023-27395 is a critical memory corruption vulnerability in SoftEther VPN, published on 12 Oct 2023. 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-2023-27395 in the wild and no public exploit code.

Affected product: SoftEther VPN. 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-2023-27395/ (Markdown: https://insights.sbomify.com/CVE-2023-27395/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-27395
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-27395
- OSV: https://osv.dev/vulnerability/CVE-2023-27395

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-27395/
Summaries are generated and may contain mistakes; the official description above is the record.