CVE-2026-81766

MEDIUMPre-NVD 6.66.6—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.6 under CISA-ADP (Vulnrichment) CVSS v3.1 (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 96% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cisa-adp, epss
Trending — 5 sources updated this week
6.6EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.6Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
6.6
EG Score
6.6(medium)
EG Risk
30(Track)
EG Risk 30/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity66% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
4%
KEV
Not listed

Published

August 30, 2026

Last Modified

August 31, 2026

Advisory Details (1)

Auto-updated Aug 31, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic🟡 PoC Available

Really Simple Security < 9.8.0 – Multisite Subsite Admin+ Arbitrary Plugin Installation via rsp_upgrade_install_plugin | CVE 2026-81766 | Plugin Vulnerabilities

https://wpscan.com/vulnerability/948d70a2-605e-4a83-8feb-eca4dbb5f948/

Vendor Advisories for CVE-2026-81766(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 9× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-31 13:28 UTCGHSA enrichment
  2. 2026-08-31 12:50 UTCEG score recompute▲ 6.60
  3. 2026-08-31 12:49 UTCGHSA enrichment
  4. 2026-08-31 12:49 UTCMITRE cvelistV5CVSS v3 → 6.6 · severity → MEDIUM
  5. 2026-08-30 19:18 UTCEPSS rescore
  6. 2026-08-30 19:17 UTCEPSS rescore
  7. 2026-08-30 07:31 UTCNVD update
  8. 2026-08-30 06:31 UTCEG score recompute
  9. 2026-08-30 06:30 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-81766?
CVE-2026-81766 is a medium vulnerability published on August 30, 2026. 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…
When was CVE-2026-81766 disclosed?
CVE-2026-81766 was first published in the National Vulnerability Database on August 30, 2026, with the most recent update on August 31, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-81766 actively exploited?
CVE-2026-81766 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 95.7% of all scored CVEs.
What is the CVSS score of CVE-2026-81766?
CVE-2026-81766 has a CVSS v3.1 base score of 6.6 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-81766?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-81766, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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