Threats / Zyxel / CVE-2017-6884
CVE-2017-6884
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-09-19
Zyxel EMG2926 Routers vulnerability
Zyxel EMG2926 routers contain a command injection vulnerability in diagnostic tools that allows remote code execution through the nslookup function, enabling attackers to execute arbitrary commands on affected devices.
Verdict
Today item, not a backlog item.
This OS command injection vulnerability in widely deployed router firmware presents severe risk. Active exploitation in ransomware campaigns and high EPSS score indicate immediate threat. Affected organizations should prioritize patching or isolating vulnerable EMG2926 devices.
CISA KEV Yes · 2023-09-184Ransomware use Flagged4EPSS 0.36519 (verify live)5CVSS 8.8 (CISA)3CISA SSVC Exploitation: active · Automatable: no · Impact: total3
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
10 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2023-09-18), flagged for known ransomware use.
Probability (EPSS)
EPSS 0.36519 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 8.8 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) · Affected: Zyxel, EMG2926 Routers. Confirm exact fixed builds in the vendor advisory.CVSS — CISA-assigned via the ADP container (CVE.org), version 3.1; the CNA left no metrics, so CISA's own score is used ahead of NVD.
Weakness (CWE)
Mapped to CWE-78 OS Command Injection — weakness family: Injection.CWE assignment from the public NVD record (may be stale); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: no · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 2356 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I identify the diagnostic nslookup endpoint and craft a malicious ping_ip parameter containing shell metacharacters to break out of the intended command context.
Business
Attackers gain unauthenticated remote code execution on network perimeter devices, establishing persistent access to internal infrastructure.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I execute system commands with router privileges to disable security controls, modify firewall rules, or establish reverse shells for command and control.
Business
Compromised routers become pivot points for lateral movement into corporate networks, bypassing external security controls.
3
Lateral reach — past segmentation narrative 3
Attacker
I deploy ransomware payloads or data exfiltration tools across the network using the router as a distribution vector.
Business
Ransomware campaigns encrypt critical business systems and threaten data breaches, resulting in operational shutdown and financial extortion.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05
Coverage & confidence
— what we know, and what we don’tEstablished (cited)
Coverage gaps — stated, not hidden
Disclosure & credit2
Catalogued by mitreCNA
Credited with finding itNo finder is named in the public CVE record or the scanned vendor advisory — attribution scoped to the sources checked.
Found an error? Propose a correction.
A correction is a cited counter-claim — it must cite a source,
gets reviewed by a second human, and is never auto-applied. See the
correction convention and our identity
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