# CVE-2018-9129: Weak cryptography in n/a

> Attackers can exploit a Bleichenbacher vulnerability in the IKE handshake to decrypt IPsec VPN traffic or bypass authentication on ZyXEL firewalls.

- **Severity:** Medium 5.9 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Aug 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-rxgc-f7rc-pv6h

## What is CVE-2018-9129?

CVE-2018-9129 is a medium-severity vulnerability in n/a, published on 15 Aug 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

ZyXEL ZyWALL/USG series devices have a Bleichenbacher vulnerability in their Internet Key Exchange (IKE) handshake implementation used for IPsec based VPN connections.

## Which versions are affected by CVE-2018-9129?

It affects 17 products.


Products: Zyxel Usg 1100 Firmware, Zyxel Usg 110 Firmware, Zyxel Usg 1900 Firmware, Zyxel Usg 20w-Vpn Firmware, Zyxel Usg 20w Firmware, Zyxel Usg 2200-Vpn Firmware, Zyxel Usg 310 Firmware, Zyxel Usg 40 Firmware, Zyxel Usg 40w Firmware, Zyxel Usg 60 Firmware, Zyxel Usg 60w Firmware, Zyxel Zywall 1100 Firmware, Zyxel Zywall 110 Firmware, Zyxel Zywall 310 Firmware, Zyxel Zywall Vpn 100 Firmware, Zyxel Zywall Vpn 300 Firmware, Zyxel Zywall Vpn 50 Firmware.

## How do I fix CVE-2018-9129?

No fix has been published for CVE-2018-9129 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-9129 being exploited?

There is no known exploitation of CVE-2018-9129 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-9129 and fix it if it is affected.

What it is: CVE-2018-9129 is a medium-severity vulnerability in n/a, published on 15 Aug 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-2018-9129 in the wild and no public exploit code.

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-2018-9129/ (Markdown: https://insights.sbomify.com/CVE-2018-9129/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-9129
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-9129
- OSV: https://osv.dev/vulnerability/CVE-2018-9129

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-9129/
Summaries are generated and may contain mistakes; the official description above is the record.