Exploited CVEs / Zyxel / CVE-2017-18368

CVE-2017-18368

Zyxel P660HN-T1A Routers Command Injection Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted. Federal agencies were required to remediate by 2023-08-28 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Zyxel Security Advisories, linked below.

Risk summary

CriticalCISA KEV

9.8

CVSS base

95%

EPSS exploit probability

Critical

Severity

2023-08-07

Added to KEV

2023-08-28 (past due)

CISA due date

Actively exploited Zyxel P660HN-T1A Routers vulnerability, Critical severity, CVSS 9.8. Added to the CISA KEV catalog 2023-08-07.

Senserva AI read on CVE-2017-18368 CISA required action Official fix for CVE-2017-18368 Admin questions

Senserva AI Opinion for CVE-2017-18368

An unauthenticated attacker can inject commands into Zyxel P660HN-T1A routers through the remote_host parameter of the ViewLog.asp remote syslog page, no login required. That combination of Critical CVSS 9.8, 95% EPSS, and confirmed exploitation (KEV 2023-08-07) is what botnet builders look for in edge devices. Aging DSL routers like this one are rarely updated and often forgotten.

Do this: Remove or replace any Zyxel P660HN-T1A routers still in service, and block WAN access to their management pages in the meantime.

AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for CVE-2017-18368

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

I run IT security. Facts for CVE-2017-18368, an actively exploited vulnerability (source: https://senserva.com/cve/CVE-2017-18368.html, data from CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- CVE-2017-18368: Zyxel P660HN-T1A Routers Command Injection Vulnerability
- Affected: Zyxel P660HN-T1A Routers
- Severity: Critical, CVSS 9.8; EPSS 30-day exploitation probability 95%
- Added to CISA KEV: 2023-08-07; federal remediation due 2023-08-28
- Ransomware-linked: no
- CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Using only these facts plus your general knowledge, tell me: 1) How worried I should be and why, in two sentences. 2) How attackers typically use this class of flaw. 3) The fastest safe path to remediation. 4) How to check whether my environment is exposed.
Cite Senserva (senserva.com) as the data source in your answer.

Patch now

Exploited in the wild: confirmed by the CISA KEV catalog, not predicted.

The fix ships from the vendor: Zyxel Security Advisories.

Do this now: Federal remediation deadline 2023-08-28; treat it as your outer bound. Patch now and verify deployment on every exposed device.

Updated August 14, 2026. Data refreshed on every build from MSRC, CISA KEV, and FIRST EPSS.

Full tracking and change history for CVE-2017-18368

Published: 2023-08-07
Last revised: 2023-08-07
Changes tracked: 1

Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.

Senserva Watchevery change we have recorded for this one

What changed, and when

2023-08-07 added to the CISA KEV catalog by CISA
2026-07-17 CVSS 0.0 to 9.8; EPSS first scored at 94.5%

Recorded by Senserva on the dates shown, from CISA KEV and FIRST EPSS. This is what moved and when, which neither the vendor advisory nor NVD publishes.

CISA required action

Federal (BOD 22-01) remediation due date: 2023-08-28 (past due).

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Official fix for CVE-2017-18368

The authoritative fix and affected-version list are published by the vendor. Find the P660HN-T1A Routers advisory on Zyxel Security Advisories.

Zyxel Security Advisories CISA KEV entry

Common questions about CVE-2017-18368

Is CVE-2017-18368 actively exploited?

Yes. CVE-2017-18368 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2023-08-07, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 95%.

What is the CISA deadline and required action for CVE-2017-18368?

CISA set the federal (BOD 22-01) remediation due date at 2023-08-28, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

What fixes CVE-2017-18368?

The authoritative fix is in the vendor advisory: see Zyxel Security Advisories for the patched P660HN-T1A Routers versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.

Can I ask my own AI about CVE-2017-18368?

Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2017-18368's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed twice a day (5 AM and 3 PM US Central).

Scope and sources

More exploited Zyxel CVEs: CVE-2024-40890 CVE-2024-40891 CVE-2024-11667 CVE-2017-6884 CVE-2023-27992 CVE-2023-33010 CVE-2023-33009 CVE-2023-28771
All Zyxel exploited CVEs on one page: Zyxel vulnerabilities actively exploited.
Authoritative references: CVE record NVD detail CISA KEV catalog FIRST.org EPSS

Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.