CVE-2021-20829Network attack vector

Arbitrary script execution via inadequate tag sanitization

Published Sep 21, 2021 · Updated Aug 3, 2024

Cross-site scripting in WESEEK GROWI 4.2.19 and earlier allows remote attackers to execute arbitrary script in a user's web browser via a crafted page. The tag-sanitization path processes attacker-controlled tags inadequately, allowing script content to reach rendered page output. The attack requires a user to access the specially crafted page; impact is browser-side script execution with confidentiality and integrity effects, not service interruption.

CVSS severity6.1
Medium
EPSS probability0.75%
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 WESEEK GROWI 4.2.19 and earlier allows remote attackers to execute arbitrary script in a user's web browser via a crafted page. The tag-sanitization path processes attacker-controlled tags inadequately, allowing script content to reach rendered page output. The attack requires a user to access the specially crafted page; impact is browser-side script execution with confidentiality and integrity effects, not service interruption.

The record

CVE
CVE-2021-20829
Published
Sep 21, 2021
Updated
Aug 3, 2024
Vendor
WESEEK, Inc.
Product
GROWI
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 21, 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=versions v4.2.19 and earlier

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

WESEEK, Inc. · GROWIversion=versions v4.2.19 and earlier

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.

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 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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