CVE-2021-20685Network attack vector

Browser script execution via undisclosed input handling

Published Apr 7, 2021 · Updated Aug 3, 2024

Cross-site scripting in daifukuya.com Kagemai 0.8.8 allows remote attackers to execute arbitrary scripts in a user's browser via unspecified vectors. The official advisory does not identify the affected page, input, or output operation that fails to neutralize attacker-controlled data. Exploitation requires a user to open an affected Kagemai page; the script then runs in that browser's security context, with confidentiality and integrity effects but no reported service interruption.

CVSS severity6.1
Medium
EPSS probability0.76%
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 daifukuya.com Kagemai 0.8.8 allows remote attackers to execute arbitrary scripts in a user's browser via unspecified vectors. The official advisory does not identify the affected page, input, or output operation that fails to neutralize attacker-controlled data. Exploitation requires a user to open an affected Kagemai page; the script then runs in that browser's security context, with confidentiality and integrity effects but no reported service interruption.

The record

CVE
CVE-2021-20685
Published
Apr 7, 2021
Updated
Aug 3, 2024
Vendor
daifukuya.com
Product
Kagemai
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 7, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.8.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

daifukuya.com · Kagemaiversion=0.8.8

Published CVSS scores

6.1JPCERT/CCCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3JPCERT/CCAV:N/AC:M/Au:N/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
Privilegesunauthenticated
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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