CVE-2021-20654Public exploitNetwork attack vector

Authenticated stored XSS via unsanitized fields

Published Feb 10, 2021 · Updated Aug 3, 2024

Stored cross-site scripting in WeKan 3.12 through 4.11 allows remote authenticated users to execute script in other users' browsers. Unsanitized card, list, checklist, subtask, comment, and other input fields persist attacker-supplied HTML or JavaScript, and malicious SVG attachments can execute when rendered inline. Login is required to plant the payload, and a victim must load the affected board or attachment; the result can read session data, alter page content, or conduct phishing, with no reported availability impact.

CVSS severity5.4
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

Stored cross-site scripting in WeKan 3.12 through 4.11 allows remote authenticated users to execute script in other users' browsers. Unsanitized card, list, checklist, subtask, comment, and other input fields persist attacker-supplied HTML or JavaScript, and malicious SVG attachments can execute when rendered inline. Login is required to plant the payload, and a victim must load the affected board or attachment; the result can read session data, alter page content, or conduct phishing, with no reported availability impact.

The record

CVE
CVE-2021-20654
Published
Feb 10, 2021
Updated
Aug 3, 2024
Vendor
WeKan
Product
WeKan
Classifications
CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 10, 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 between 3.12 and 4.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

WeKan · WeKanversion=versions between 3.12 and 4.11

Published CVSS scores

5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
3.5NVDAV:N/AC:M/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 exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Stored XSS

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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