Low severity · published Aug 4, 2026
CVE-2026-11366
MonsterInsights < 11.1.0 - Unauthenticated Measurement Protocol Secret Update via Empty-Key HMAC Bypass
3.7
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 16% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MO
MonsterInsights ·
before 11.1.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-11366
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-11366
wpscan.com
https://wpscan.com/vulnerability/283331ca-cc2e-4c2c-9e3b-2e8c6f0c84d2/
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