MonsterInsights accepts forged empty-key configuration signatures
MonsterInsights before 11.1.0 validates an unauthenticated AJAX request with an HMAC key that is empty when the plugin is not connected to Google Analytics. An unauthenticated attacker can calculate a valid signature under that configuration and overwrite a MonsterInsights setting, disrupting server-side analytics in Manual GA4 mode. The public advisory does not disclose the AJAX action, signed fields, configuration parameter or update function.
- Component
- MonsterInsights
- Plugin slug
monsterinsights- Affected
- < 11.1.0
- Safe version
11.1.0- Published
- Aug 04, 2026
This CVE was published Aug 04, 2026 and is one of 3 known issues for this plugin.
Update, patch or deactivate.
Update MonsterInsights to 11.1.0 or later. Review Manual GA4 and server-side analytics settings for unauthorized changes if the plugin was unconnected while vulnerable.
A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.
Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.
Technical 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.
CVE / CNA vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N