CVE-2021-4431Network attack vector

Cross-site scripting via unencoded FileMaker output

Published Nov 7, 2023 · Updated Aug 3, 2024

Cross-site scripting in FMDataAPI 22 and earlier allows remote authenticated users to execute scripts through crafted FileMaker values. FMDataAPI_Sample.php writes metadata, record fields, errors, and script results into HTML without output encoding. Exploitation requires malicious content in returned FileMaker data and a user who loads the deployed sample page, enabling script execution in that user's browser.

CVSS severity3.5
Low
EPSS probability0.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in FMDataAPI 22 and earlier allows remote authenticated users to execute scripts through crafted FileMaker values. FMDataAPI_Sample.php writes metadata, record fields, errors, and script results into HTML without output encoding. Exploitation requires malicious content in returned FileMaker data and a user who loads the deployed sample page, enabling script execution in that user's browser.

The record

CVE
CVE-2021-4431
Published
Nov 7, 2023
Updated
Aug 3, 2024
Vendor
msyk
Product
FMDataAPI
Classifications
CWE-79, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 7, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record 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=22

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

msyk · FMDataAPIversion=22

Published CVSS scores

3.5VulDBCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
3.5VulDBCVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.0VulDBAV:N/AC:L/Au:S/C:N/I:P/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1190Exploit Public-Facing Application

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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