CVE-2021-27907Public exploitNetwork attack vector

Stored XSS via unsanitized SVG in Dashboard Markdown

Published Mar 5, 2021 · Updated Feb 13, 2025

Stored XSS in Dashboard Markdown in Apache Superset 0.38.0 and earlier allows remote authenticated users to execute JavaScript in viewers' browsers. A crafted div containing an SVG element with JavaScript is stored without effective neutralization and rendered when a legitimate user opens the dashboard. An authenticated user must create the Markdown component, and execution occurs only after another user visits the affected dashboard, exposing that user's browser context to unauthorized actions.

CVSS severity5.4
Medium
EPSS probability86.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Dashboard Markdown in Apache Superset 0.38.0 and earlier allows remote authenticated users to execute JavaScript in viewers' browsers. A crafted div containing an SVG element with JavaScript is stored without effective neutralization and rendered when a legitimate user opens the dashboard. An authenticated user must create the Markdown component, and execution occurs only after another user visits the affected dashboard, exposing that user's browser context to unauthorized actions.

The record

CVE
CVE-2021-27907
Published
Mar 5, 2021
Updated
Feb 13, 2025
Vendor
The Apache Software Foundation
Product
Apache Superset
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record 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=Apache Superset <=0.38.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Apache Software Foundation · Apache Supersetversion=Apache Superset <=0.38.0

Published CVSS scores

5.4GitHub Security Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
3.5NIST NVDAV: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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')
T1059.007JavaScript

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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