CVE-2026-66599Network attack vector

Browser script execution via undisclosed input handling

Published Aug 24, 2026 · Updated Aug 24, 2026

Cross-site scripting in StellarWP WPComplete 2.9.5.6 and earlier allows remote attackers to inject script through unauthenticated requests. The CNA and its sole public reference do not identify the affected endpoint, parameter, or input-to-output operation. A visitor must interact with the affected output; successful exploitation runs script in that visitor's browser context and permits access to data and actions available to the session.

CVSS severity7.1
High
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in StellarWP WPComplete 2.9.5.6 and earlier allows remote attackers to inject script through unauthenticated requests. The CNA and its sole public reference do not identify the affected endpoint, parameter, or input-to-output operation. A visitor must interact with the affected output; successful exploitation runs script in that visitor's browser context and permits access to data and actions available to the session.

The record

CVE
CVE-2026-66599
Published
Aug 24, 2026
Updated
Aug 24, 2026
Vendor
Liquid Web
Product
WPComplete
Classifications
CWE-79, CAPEC-588, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a <=2.9.5.6 changes=[{"at":"2.9.5.7","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Liquid Web · WPCompleteversion=n/a <=2.9.5.6 changes=[{"at":"2.9.5.7","status":"unaffected"}]

Published CVSS scores

7.1PatchstackCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC-588DOM-Based XSS
T1189Drive-by Compromise

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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