CVE-2026-87111Network attack vector

Unauthenticated stored XSS via unsanitized Referer header

Published Oct 16, 2026 · Updated Oct 16, 2026

Stored XSS in User Registration & Membership Pro 6.2.9 and earlier allows remote attackers to inject scripts via HTTP Referer headers. The AJAX processing path stores header content without sufficient sanitization and renders it without sufficient escaping; the supplied record does not name the handler. Only the premium build is affected, its required nonce is exposed to anonymous visitors, and script execution requires a user to view an injected page.

CVSS severityUnavailable
Unscored
EPSS probability0.19%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in User Registration & Membership Pro 6.2.9 and earlier allows remote attackers to inject scripts via HTTP Referer headers. The AJAX processing path stores header content without sufficient sanitization and renders it without sufficient escaping; the supplied record does not name the handler. Only the premium build is affected, its required nonce is exposed to anonymous visitors, and script execution requires a user to view an injected page.

The record

CVE
CVE-2026-87111
Published
Oct 16, 2026
Updated
Oct 16, 2026
Vendor
WPEverest
Product
User Registration & Membership Pro
Classifications
T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=0 <=6.2.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

WPEverest · User Registration & Membership Proversion=0 <=6.2.9

Published CVSS scores

No CVSS assessment is available in this record.

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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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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