CVE-2026-66703Network attack vector

Contributor-level stored script execution via optin block

Published Aug 6, 2026 · Updated Aug 6, 2026

Stored cross-site scripting in Proper Fraction MailOptin 1.2.78.0 and earlier allows remote authenticated users to execute script in victim browsers. The vendor identifies the optin block as the affected locus, but public records do not disclose the input, storage path, or faulty output operation. Contributor access and a separate user's interaction are required; execution occurs in the site's origin and can read or alter browser-accessible data.

CVSS severity6.5
Medium
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in Proper Fraction MailOptin 1.2.78.0 and earlier allows remote authenticated users to execute script in victim browsers. The vendor identifies the optin block as the affected locus, but public records do not disclose the input, storage path, or faulty output operation. Contributor access and a separate user's interaction are required; execution occurs in the site's origin and can read or alter browser-accessible data.

The record

CVE
CVE-2026-66703
Published
Aug 6, 2026
Updated
Aug 6, 2026
Vendor
ProfilePress Membership Team
Product
MailOptin
Classifications
CWE-79, CAPEC-592, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 6, 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 <=1.2.78.0 changes=[{"at":"1.2.78.1","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ProfilePress Membership Team · MailOptinversion=n/a <=1.2.78.0 changes=[{"at":"1.2.78.1","status":"unaffected"}]

Published CVSS scores

6.5PatchstackCVSS:3.1/AV:N/AC:L/PR:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC-592Stored XSS
T1059.007JavaScript/JScript

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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