CVE-2021-42565Public exploitNetwork attack vector

Reflected XSS via unescaped UID parameter

Published Oct 18, 2021 · Updated Aug 4, 2024

Cross-site scripting in myfactory.FMS before 7.1-912 allows remote attackers to execute JavaScript in a user's browser via the UID parameter. The login form reflects UID directly into the HTML input value without output encoding, allowing attacker-supplied markup and script to execute when the response is rendered. Exploitation requires a victim to open an attacker-prepared link; script execution can alter the page or capture credentials and user-visible data, while no service interruption is reported.

CVSS severity6.1
Medium
EPSS probability5.83%
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 myfactory.FMS before 7.1-912 allows remote attackers to execute JavaScript in a user's browser via the UID parameter. The login form reflects UID directly into the HTML input value without output encoding, allowing attacker-supplied markup and script to execute when the response is rendered. Exploitation requires a victim to open an attacker-prepared link; script execution can alter the page or capture credentials and user-visible data, while no service interruption is reported.

The record

CVE
CVE-2021-42565
Published
Oct 18, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1NVDCVSS: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.

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

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

Public exploit references

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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