CVE-2021-21029Public exploitNetwork attack vector

Browser script execution via decoded file parameter

Published Feb 11, 2021 · Updated Sep 16, 2024

Reflected XSS in Adobe Commerce 2.4.1 and earlier allows remote attackers to execute JavaScript in an administrator's browser. The downloadCss route accepts a Base64-encoded payload in the file path parameter and reflects the decoded value without safe output encoding. Exploitation requires the hidden admin path and user interaction; with secret URL keys enabled by default, the attacker also needs a valid key, and execution is confined to the victim's browser.

CVSS severity4.8
Medium
EPSS probability84.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in Adobe Commerce 2.4.1 and earlier allows remote attackers to execute JavaScript in an administrator's browser. The downloadCss route accepts a Base64-encoded payload in the file path parameter and reflects the decoded value without safe output encoding. Exploitation requires the hidden admin path and user interaction; with secret URL keys enabled by default, the attacker also needs a valid key, and execution is confined to the victim's browser.

The record

CVE
CVE-2021-21029
Published
Feb 11, 2021
Updated
Sep 16, 2024
Vendor
Adobe
Product
Adobe Commerce
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=unspecified <=2.3.6
  2. Affected versionversion=unspecified <=2.4.0-p1
  3. Affected versionversion=unspecified <=2.4.1
  4. Affected versionversion=unspecified <=None

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Adobe · Adobe Commerceversion=unspecified <=2.3.6; version=unspecified <=2.4.0-p1; version=unspecified <=2.4.1; version=unspecified <=None

Published CVSS scores

4.8Adobe Systems IncorporatedCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/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 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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