What’s Vulnerable › Vulnerabilities
CVE-2026-11366: MonsterInsights < 11.1.0 - Unauthenticated Measurement Protocol Secret Update via Empty-Key HMAC Bypass
- Severity: low (CVSS 3.7 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-08-04 · updated 2026-08-26
- Weakness: CWE-287
Description
The MonsterInsights WordPress plugin before 11.1.0 does not correctly validate the signature on one of its unauthenticated AJAX actions: when the MonsterInsights WordPress plugin before 11.1.0 is not connected to Google Analytics the HMAC signing key is empty, which lets unauthenticated attackers forge a valid signature and overwrite a MonsterInsights WordPress plugin before 11.1.0 configuration value, disrupting the MonsterInsights WordPress plugin before 11.1.0's server-side analytics in Manual GA4 mode.
Affected products
- MonsterInsights: before 11.1.0 — fixed in 11.1.0
How to fix
Upgrade to a fixed version: MonsterInsights 11.1.0. Check the vendor advisory for mitigations.
References
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