Really Simple Security < 9.8.0 - Multisite Subsite Admin+ Arbitrary Plugin Installation via rsp_upgrade_install_plugin (CVE-2026-81766) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-81766

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

Answer in brief

CVE-2026-81766 records a Unknown severity vulnerability in Really Simple Security < 9.8.0 - Multisite Subsite Admin+ Arbitrary Plugin Installation via rsp_upgrade_install_plugin. The current sources do not mark it as known exploited. The current feed maps Unknown/Really Simple Security (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 30, 2026Updated Aug 30, 2026Source checked Aug 30, 2026First seen by HOL Aug 30, 2026Material review Aug 30, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Unknown/Really Simple Security (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Unknown/Really Simple Securitygeneric	>=0 <9.8.0	9.8.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for Unknown/Really Simple Security.
Review the reported fix. Update Unknown/Really Simple Security to 9.8.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 30, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 30, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 30, 2026

Sources and claim methodology

Source referencewpscan.com

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.