CVE-2026-11366Public exploitNetwork attack vector

Analytics disruption via empty-key HMAC signature forgery

Published Aug 4, 2026 · Updated Aug 4, 2026

Improper authentication in MonsterInsights before 11.1.0 allows remote attackers to disrupt server-side analytics via a forged AJAX request. The monsterinsights_push_mp_token action verifies attacker-controlled parameters with an HMAC-MD5 key that is empty when no OAuth key exists, allowing a forged signature to overwrite measurement_protocol_secret. The site must use Manual GA4 mode with a stored Measurement ID and no OAuth key; outbound GA4 requests then use the attacker-chosen secret while the Measurement ID remains unchanged.

CVSS severity3.7
Low
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authentication in MonsterInsights before 11.1.0 allows remote attackers to disrupt server-side analytics via a forged AJAX request. The monsterinsights_push_mp_token action verifies attacker-controlled parameters with an HMAC-MD5 key that is empty when no OAuth key exists, allowing a forged signature to overwrite measurement_protocol_secret. The site must use Manual GA4 mode with a stored Measurement ID and no OAuth key; outbound GA4 requests then use the attacker-chosen secret while the Measurement ID remains unchanged.

The record

CVE
CVE-2026-11366
Published
Aug 4, 2026
Updated
Aug 4, 2026
Vendor
Monster Insights LLC
Product
MonsterInsights
Classifications
CWE-287, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <11.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Monster Insights LLC · MonsterInsightsversion=0 <11.1.0

Published CVSS scores

3.7CISA-ADPCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-287Improper Authentication
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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