CVE-2026-11976Known exploitationNetwork attack vector

Site takeover via injected update-package backdoor

Published Aug 6, 2026 · Updated Aug 6, 2026

Supply-chain backdoor in MonsterInsights Pro 10.2.0 through 10.2.2 allows remote attackers to take control of WordPress sites. The compromised official S3 update bucket inserted class-system-check.php, which redirects future plugin updates, creates a persistent administrator account, and accepts an authentication-bypass GET parameter. The malicious PHP reaches a site when an affected official package is installed or updated, and its administrator access persists after plugin removal.

CVSS severity10.0
Critical
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Supply-chain backdoor in MonsterInsights Pro 10.2.0 through 10.2.2 allows remote attackers to take control of WordPress sites. The compromised official S3 update bucket inserted class-system-check.php, which redirects future plugin updates, creates a persistent administrator account, and accepts an authentication-bypass GET parameter. The malicious PHP reaches a site when an affected official package is installed or updated, and its administrator access persists after plugin removal.

The record

CVE
CVE-2026-11976
Published
Aug 6, 2026
Updated
Aug 6, 2026
Vendor
Monster Insights LLC
Product
MonsterInsights Pro
Classifications
CWE-912, T1195.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 11, 2026Exploitation reportedCompromise of the official MonsterInsights update bucket
  2. Aug 6, 2026CVE publishedPublication date reported by the CVE source.
  3. Aug 6, 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=10.2.0 <11.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Monster Insights LLC · MonsterInsights Proversion=10.2.0 <11.0.0

Published CVSS scores

10.0WPScanCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

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 exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-912Hidden Functionality
T1195.002Compromise Software Supply Chain

Public exploit references

No public exploit references are available in this record.

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Reported exploitation

Technologies

Your stack

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Your stack

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