Really Simple Security < 9.8.0 - Multisite Subsite Admin+ Arbitrary Plugin Installation via rsp_upgrade_install_plugin

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-81766
StatePUBLISHED
AssignerWPScan
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-30 07:17:21 UTC
Updated2026-08-31 13:18:28 UTC
DescriptionThe 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.

Risk And Classification

Primary CVSS: v3.1 6.6 MEDIUM from ADP

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001470000 probability, percentile 0.042660000 (date 2026-08-30)

Problem Types: CWE-269 | CWE-269 Improper Privilege Management | CWE-269 CWE-269 Improper Privilege Management

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED6.6MEDIUMCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary6.6MEDIUMCVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Unknown Really Simple Security affected 9.8.0 semver Not specified

References

ReferenceSourceLinkTags
wpscan.com/vulnerability/948d70a2-605e-4a83-8feb-eca4dbb5f948 [email protected] wpscan.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Charles Vosburgh (en)

CNA: WPScan (en)

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