# CVE-2018-8929: Security feature bypass in SSL VPN Client

> Remote attackers can intercept VPN traffic via man-in-the-middle attacks due to improper endpoint restrictions in the Synology SSL VPN Client.

- **Severity:** High 7.3 (`CVSS:3.0/AV:N/AC:L/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:** 6 Jul 2018
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-x728-vr6f-27f3

## What is CVE-2018-8929?

CVE-2018-8929 is a high-severity vulnerability in Synology SSL VPN Client, published on 6 Jul 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Improper restriction of communication channel to intended endpoints vulnerability in HTTP daemon in Synology SSL VPN Client before 1.2.4-0224 allows remote attackers to conduct man-in-the-middle attacks via a crafted payload.

Weakness: CWE-417, CWE-319 (Cleartext Transmission of Sensitive Information)

## Which versions are affected by CVE-2018-8929?

It affects 1 product.


Products: Synology Ssl Vpn Client.

## How do I fix CVE-2018-8929?

No fix has been published for CVE-2018-8929 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-8929 being exploited?

There is no known exploitation of CVE-2018-8929 in the wild and no public exploit code.

## Other vulnerabilities in Synology SSL VPN Client

- [CVE-2018-13283](https://insights.sbomify.com/CVE-2018-13283/): Security feature bypass in SSL VPN Client (high 8.8)
- [CVE-2021-47961](https://insights.sbomify.com/CVE-2021-47961/): Information disclosure in Synology SSL VPN Client (high 8.1)
- [CVE-2021-47960](https://insights.sbomify.com/CVE-2021-47960/): Information disclosure in Synology SSL VPN Client (medium 6.5)
- [CVE-2023-5748](https://insights.sbomify.com/CVE-2023-5748/): Memory corruption in Synology SSL VPN Client (low 3.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-8929 and fix it if it is affected.

What it is: CVE-2018-8929 is a high-severity vulnerability in Synology SSL VPN Client, published on 6 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-2018-8929 in the wild and no public exploit code.

Affected product: Synology SSL VPN Client. 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-2018-8929/ (Markdown: https://insights.sbomify.com/CVE-2018-8929/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-8929
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-8929
- OSV: https://osv.dev/vulnerability/CVE-2018-8929

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-8929/
Summaries are generated and may contain mistakes; the official description above is the record.