Vulnerability in Monsterinsights Pro

CVE-2026-11976

The official MonsterInsights Pro update distribution bucket (`monster-insights.s3.amazonaws.com`) was compromised. Both the current release (10.2.2) and the version MonsterInsights rolled back to (10.2.0) contain a malicious file, `class-system-check.php`. Three distinct variants were observed on 2026-06-11, all sharing the same AES-256-GCM key, confirming a single threat actor. The attacker retains write access to the S3 bucket and has been actively iterating on the payload throughout the day.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.005 (44.3th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 44th percentile — 44.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-11976: held from 0.005 to 0.005.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

  • Monsterinsights Pro — versions 10.2.0

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-11976?
CVE-2026-11976 is a critical-severity vulnerability in Monsterinsights Pro, classified under Hidden Functionality. CVSS score: 10.0/10. Published 2026-08-06.
How severe is CVE-2026-11976?
Critical severity. CVSS v3 base score is 10.0 out of 10.