# CVE-2025-25566: Denial of service in n/a

> An attacker can cause a denial of service in SoftEtherVPN via a memory leak in the UnixMemoryAlloc function, though the impact is disputed as minor.

- **Severity:** Medium 5.6 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Mar 2025
- **Updated:** 19 Jul 2025
- **Also known as:** GHSA-8hg9-rcgr-qwwm

## What is CVE-2025-25566?

CVE-2025-25566 is a medium-severity denial of service vulnerability in n/a, published on 12 Mar 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Memory Leak vulnerability in SoftEtherVPN 5.02.5187 allows an attacker to cause a denial of service via the UnixMemoryAlloc function. NOTE: the Supplier disputes this because the behavior is limited to a single allocation of a few hundred bytes with a command-line tool.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2025-25566?

It affects 1 product.


Products: Softether Vpn.

## How do I fix CVE-2025-25566?

No fix has been published for CVE-2025-25566 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-25566 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-25566 exists.

## Other vulnerabilities in n/a

- [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-2023-27395](https://insights.sbomify.com/CVE-2023-27395/): Memory corruption in SoftEther VPN (critical 9.0)
- [CVE-2023-32634](https://insights.sbomify.com/CVE-2023-32634/): Auth bypass in SoftEther VPN (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-25566 and fix it if it is affected.

What it is: CVE-2025-25566 is a medium-severity denial of service vulnerability in n/a, published on 12 Mar 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-25566 exists.

Affected product: n/a. 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-2025-25566/ (Markdown: https://insights.sbomify.com/CVE-2025-25566/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-25566
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-25566
- OSV: https://osv.dev/vulnerability/CVE-2025-25566

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-25566/
Summaries are generated and may contain mistakes; the official description above is the record.