CVE-2021-24563Public exploitNetwork attack vector

Stored XSS via unrestricted HTML upload

Published Oct 11, 2021 · Updated Aug 3, 2024

Cross-site scripting in Frontend Uploader through 1.3.2 allows remote attackers to execute JavaScript in a visitor's browser via uploaded HTML. The upload form accepts HTML files without blocking or neutralizing script content, and the stored file serves that content when opened. A visitor must access the uploaded file for execution, which can alter the page context or expose data available to that browser session.

CVSS severity6.1
Medium
EPSS probability26.38%
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 Frontend Uploader through 1.3.2 allows remote attackers to execute JavaScript in a visitor's browser via uploaded HTML. The upload form accepts HTML files without blocking or neutralizing script content, and the stored file serves that content when opened. A visitor must access the uploaded file for execution, which can alter the page context or expose data available to that browser session.

The record

CVE
CVE-2021-24563
Published
Oct 11, 2021
Updated
Aug 3, 2024
Vendor
Rinat Khaziev
Product
Frontend Uploader
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 11, 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=1.3.2 <=1.3.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Rinat Khaziev · Frontend Uploaderversion=1.3.2 <=1.3.2

Published CVSS scores

6.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3NVDAV: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.

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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 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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