kstover Ninja Forms Plugin up to 3.15.5 on WordPress Input Sanitization nf_ajax_submit formData.extra cross site scripting

CVSS Meta Temp Score
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CTI Interest Score
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5.7$0-$5k3.82

Summaryinfo

A vulnerability was found in kstover Ninja Forms Plugin up to 3.15.5 and classified as problematic. The affected element is the function nf_ajax_submit of the component Input Sanitization. The manipulation of the argument formData.extra results in cross site scripting. This vulnerability was named CVE-2026-109997. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in kstover Ninja Forms Plugin up to 3.15.5. It has been classified as problematic. Affected is the function nf_ajax_submit of the component Input Sanitization. The manipulation of the argument formData.extra with an unknown input leads to a cross site scripting vulnerability. CWE is classifying the issue as CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. This is going to have an impact on integrity. CVE summarizes:

The Ninja Forms – Contact Form Builder with Calculators, Quizzes, Signatures & AI Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'formData.extra' parameter in all versions up to, and including, 3.15.5 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The nf_ajax_submit endpoint issues a valid nonce to any requester on failure, effectively neutralizing the nonce check and making exploitation trivially achievable in a single unauthenticated request.

The advisory is shared for download at wordfence.com. This vulnerability is traded as CVE-2026-109997 since 10/13/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.007.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.7
VulDB Meta Temp Score: 5.7

VulDB Base Score: 4.3
VulDB Temp Score: 4.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.2
CNA Vector (Wordfence): 🔒

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Cross site scripting
CWE: CWE-79 / CWE-94 / CWE-74
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

10/13/2026 CVE reserved
10/31/2026 +18 days Advisory disclosed
10/31/2026 +0 days VulDB entry created
10/31/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: wordfence.com
Status: Not defined

CNA: Wordfence
CVE: CVE-2026-109997 (🔒)

GCVE (CVE): GCVE-0-2026-109997
GCVE (VulDB): GCVE-100-429468

Entryinfo

Created: 10/31/2026 07:00
Changes: 10/31/2026 07:00 (65)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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