PatchTheCVECVE-2017-18371: The ZyXEL P660HN-T1A v2 TCLinux Fw #7.3.37.6 router distributed by TrueOnline has three user accounts with def
CVE-2017-18371 is a critical-severity flaw (CVSS 9.8) affecting 5200w-t firmware, p660hn-t1a v2 firmware, p660hn-t1a v1 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
The ZyXEL P660HN-T1A v2 TCLinux Fw #7.3.37.6 router distributed by TrueOnline has three user accounts with default passwords, including two hardcoded service accounts: one with the username true and password true, and another with the username supervisor and password zyad1234. These accounts can be used to login to the web interface, exploit authenticated command injections, and change router settings for malicious purposes.
Why this priority
- Critical severity
- EPSS top 2%: very likely to be exploited
- Public exploit reference
- Remotely exploitable, no login, no user action
- On your watchlist
A fixed release or distro patch exists.
Risk facts
| CVSS score | 9.8 (Critical) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 22.5% (top 2%) |
| CISA exploited list | No |
| Weakness | CWE-798 |
| Published | 2019-05-02 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Exact fixes by distribution
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- Write-up: raw.githubusercontent.com/pedrib/PoC/master/advisories/zyxel_trueonline.txt
- Write-up: seclists.org/fulldisclosure/2017/Jan/40
- Write-up: ssd-disclosure.com/index.php/archives/2910
- Metasploit: TrueOnline / ZyXEL P660HN-T v2 Router Authenticated Command Injection
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2017-18371?
5200w-t firmware: mitigate or apply the listed mitigation; p660hn-t1a v2 firmware: mitigate or apply the listed mitigation; p660hn-t1a v1 firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2017-18371 being exploited?
CVE-2017-18371 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2017-18371 affect?
CVE-2017-18371 affects 5200w-t firmware, p660hn-t1a v2 firmware, p660hn-t1a v1 firmware. Severity is critical (CVSS 9.8). The ZyXEL P660HN-T1A v2 TCLinux Fw #7.3.37.6 router distributed by TrueOnline has three user accounts with default passwords, including two hardcoded service accounts: one with the username true and password true, and another with the usern
How urgent is CVE-2017-18371?
Priority 74/100. Critical severity; EPSS top 2%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist
Software pages
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