Privilege escalation in Really Simple Security

CVE-2026-81766

The Really Simple Security WordPress plugin before 9.8.0 does not check that the user is allowed to install Really Simple Security WordPress plugin before 9.8.0 before installing one from a user-supplied URL, allowing an administrator of a subsite on a multisite network to install and execute arbitrary code in the network-shared Really Simple Security WordPress plugin before 9.8.0 directory, which WordPress otherwise reserves to the network administrator. Exploitation requires the network administrator to have enabled the Really Simple Security WordPress plugin before 9.8.0 administration menu for subsites, which is not the default.

Vulnerability class: Privilege Escalation

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.6 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.004 (36.2th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 36.2% 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-2026-81766: held from 0.003 to 0.004.

EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.002

Affected products

  • Really Simple Security

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-81766?
CVE-2026-81766 is a medium-severity vulnerability in Really Simple Security, classified under Improper Privilege Management. CVSS score: 6.6/10. Published 2026-08-30.
How severe is CVE-2026-81766?
Medium severity. CVSS v3 base score is 6.6 out of 10.