CVE-2026-4160Network attack vector

Unauthenticated payment status tampering via unchecked submission ID

Published Apr 16, 2026 · Updated Apr 16, 2026

IDOR in the Stripe SCA endpoint in WPManageNinja Fluent Forms 6.1.21 allows remote attackers to alter pending submission payment status. The AJAX handler accepts a user-controlled submission_id and updates the referenced submission without authorization or ownership validation. No account or user interaction is required; knowledge or a guess of a pending submission ID is enough to set its payment status to failed.

CVSS severity5.3
Medium
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

IDOR in the Stripe SCA endpoint in WPManageNinja Fluent Forms 6.1.21 allows remote attackers to alter pending submission payment status. The AJAX handler accepts a user-controlled submission_id and updates the referenced submission without authorization or ownership validation. No account or user interaction is required; knowledge or a guess of a pending submission ID is enough to set its payment status to failed.

The record

CVE
CVE-2026-4160
Published
Apr 16, 2026
Updated
Apr 16, 2026
Vendor
Mahmudul Hasan Arif
Product
Fluent Forms
Classifications
CWE-639, T1565.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 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=6.1.21

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mahmudul Hasan Arif · Fluent Formsversion=6.1.21

Published CVSS scores

5.3WordfenceCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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-639Authorization Bypass Through User-Controlled Key
T1565.001Stored Data Manipulation

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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