KEV Intelligence

Vulnerability report

Active exploitation observed Confirmed confidence Not in CISA KEV

CVE-2025-34037

E4200 Command Injection

Linksys / E4200 · affected before 1.0.06

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Severity
CVSS 10.0 · Critical
Confidence
Confirmed
Exploit status
Observed in sensors
EPSS
90.6%
First observed
07 Jul 2026
Last observed
07 Aug 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2025-34037 is an unauthenticated vulnerability affecting Linksys E4200 and 10 other products. An OS command injection vulnerability exists in various models of E-Series Linksys routers via the /tmUnblock.cgi and...

Is it exploited?

Yes. KEV Intelligence sensors observed exploitation attempts with confirmed confidence.

Who is affected?

Linksys / E4200 affected before 1.0.06.

What should we do?

Patch immediately, validate internet-facing exposure, and monitor for matching requests.

Overview

E4200 Command Injection

An OS command injection vulnerability exists in various models of E-Series Linksys routers via the /tmUnblock.cgi and /hndUnblock.cgi endpoints over HTTP on port 8080. The CGI scripts improperly process user-supplied input passed to the ttcp_ip parameter without sanitization, allowing unauthenticated attackers to inject shell commands.

This vulnerability was reported to be exploited in the wild by the "TheMoon" worm  in 2014 to deploy a MIPS ELF payload, enabling arbitrary code execution on the router. Additionally, this vulnerability may affect other Linksys products to include, but not limited to, WAG/WAP/WES/WET/WRT-series router models and Wireless-N access points and routers. Exploitation evidence was observed by the Shadowserver Foundation on 2025-02-06 UTC.

Vendor Product Affected Status
Linksys E4200 Before 1.0.06 Affected
Linksys E3200 Before 1.0.05 Affected
Linksys E3000 Before 1.0.06 Affected
Linksys E2500 v1/v2 Before 2.0.00 Affected
Linksys E2100L v1 Through 1.0.05 Affected
Linksys E2000 0 Affected
Linksys E1550 Through 1.0.03 Affected
Linksys E1500 v1 Before 1.0.06 Affected
Linksys E1200 v1 Through 1.0.04 Affected
Linksys E1000 v1 Before 2.1.03 Affected
Linksys E900 v1 Before 1.0.04 Affected
View vendor advisory (opens in new tab)
Published
24 Jun 2025
Exploitation Reported
01 Jun 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

edge

CVE References

Exploitation evidence

Why KEV Intelligence marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CVE

Recorded 01 Jun 2026

Independent exploitation attestation added to the KEV Intelligence record.

Active exploitation observed

KEV Intelligence sensor

First observed 07 Jul 2026

First-party sensor telemetry confirms matching exploitation attempts.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the KEV Intelligence Pro API.

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Source Added
The Shadowserver First 2026-05-28 00:00 UTC
KEV Intelligence 2026-08-06 12:51 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

First-party evidence of exploitation activity

Aggregate observations show the scale, recency, and distribution of activity without overstating sparse data.

8

Attempts observed

5

Unique attacker IPs

3

Attacker countries

CN · DE · NL

3

Sensors observed

Exploitation attempts over the last 45 days

Daily events observed by KEV Intelligence sensors

Updated 19 Aug 2026

0
2
0
40
6
14
16
2
28
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
6
0
0
0
0
0
0
0
0
0
0
0
0
6 Jul 15 Jul 24 Jul 2 Aug 19 Aug

First observed 07 Jul 2026 · Last observed 07 Aug 2026

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Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
3
User-Agents
1

Raw values available in Pro and Enterprise.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No KEV Intelligence virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

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Attacker IP Indicators

Attacker IP indicators observed · available in Pro and Enterprise.

Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.

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Risk and context

Severity, weaknesses, and research context

CVSS v4.0

10.0 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

EPSS

90.6%

Weaknesses

Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') CWE-78

Timeline

From disclosure to observed exploitation

  1. Observed by KEV Intelligence sensors

    Evidence-backed exploitation signal

  2. Indicators of compromise added (10)

    Indicators of compromise recorded

  3. Added to KEV Intelligence KEV Feed

    High-confidence, third-party attested exploitation

  4. CVE published

    Vulnerability disclosed publicly

  5. CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2025-34037

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2025-34037",
  "confidence": "Confirmed",
  "cvss_score": 10.0,
  "cvss_estimated": false,
  "epss_score": 0.90628,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 8, "sensors": 3 }
}

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