CVE-2021-20749Network attack vector

Authenticated script execution via undisclosed injection vector

Published Jun 28, 2021 · Updated Aug 3, 2024

Cross-site scripting in nendeb Fudousan plugin editions 5.7.0 and earlier allows remote authenticated users to inject scripts. Neither nendeb nor JPCERT/CC has disclosed the affected parameter, request handler, or output context that fails to neutralize attacker-controlled input. An authenticated attacker must plant the payload and a site user must access the affected content, causing the script to execute in that user's browser.

CVSS severity5.4
Medium
EPSS probability0.99%
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 nendeb Fudousan plugin editions 5.7.0 and earlier allows remote authenticated users to inject scripts. Neither nendeb nor JPCERT/CC has disclosed the affected parameter, request handler, or output context that fails to neutralize attacker-controlled input. An authenticated attacker must plant the payload and a site user must access the affected content, causing the script to execute in that user's browser.

The record

CVE
CVE-2021-20749
Published
Jun 28, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 28, 2021CVE 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.4JPCERT/CCCVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
4.0JPCERT/CCAV: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')
T1189Drive-by Compromise

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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