CVE-2024-11326Network attack vector

Reflected XSS via unescaped add_query_arg URL

Published Dec 3, 2024 · Updated Apr 8, 2026

Reflected XSS in Campaign Monitor Forms by Optin Cat 2.5.7 and earlier allows remote attackers to inject scripts through a crafted URL. In includes/eoi-subscribers.php, a URL built with add_query_arg is emitted without appropriate output escaping, allowing attacker-controlled URL data to enter HTML. A victim must follow the crafted link, after which the script runs in the visitor's browser under the affected site's origin.

CVSS severity6.1
Medium
EPSS probability0.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in Campaign Monitor Forms by Optin Cat 2.5.7 and earlier allows remote attackers to inject scripts through a crafted URL. In includes/eoi-subscribers.php, a URL built with add_query_arg is emitted without appropriate output escaping, allowing attacker-controlled URL data to enter HTML. A victim must follow the crafted link, after which the script runs in the visitor's browser under the affected site's origin.

The record

CVE
CVE-2024-11326
Published
Dec 3, 2024
Updated
Apr 8, 2026
Vendor
Fatcat Apps
Product
Campaign Monitor Forms by Optin Cat
Classifications
CWE-79
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 3, 2024CVE publishedPublication date reported by the CVE source.
  2. Apr 8, 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 <=2.5.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fatcat Apps · Campaign Monitor Forms by Optin Catversion=0 <=2.5.7

Published CVSS scores

6.1WordfenceCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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.

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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')

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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