CVE-2024-6520Network attack vector

Stored XSS via unsanitized custom error messages

Published Jul 27, 2024 · Updated Apr 8, 2026

Stored XSS in Fluent Forms 5.1.19 and earlier allows remote authenticated users to inject scripts through custom error messages. FormValidationService passed administrator-defined validation messages into error responses without HTML sanitization, allowing saved markup to reach rendered forms. Administrator access is required, and exposure is limited to multisite sites or installations with unfiltered_html disabled; accessing an affected form executes the stored script.

CVSS severity4.4
Medium
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Fluent Forms 5.1.19 and earlier allows remote authenticated users to inject scripts through custom error messages. FormValidationService passed administrator-defined validation messages into error responses without HTML sanitization, allowing saved markup to reach rendered forms. Administrator access is required, and exposure is limited to multisite sites or installations with unfiltered_html disabled; accessing an affected form executes the stored script.

The record

CVE
CVE-2024-6520
Published
Jul 27, 2024
Updated
Apr 8, 2026
Vendor
10Web
Product
Form Maker by 10Web
Classifications
CWE-79, T1203
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Jul 27, 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 <=5.1.19

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

10Web · Form Maker by 10Webversion=0 <=5.1.19
Mahmudul Hasan Arif · Fluent Formsversion=0 <=5.1.19

Published CVSS scores

4.8OSVCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
4.4WordfenceCVSS:3.1/AV:N/AC:H/PR:H/UI:N/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.

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

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

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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