How severe is CVE-2021-21029?

CVE-2021-21029 has a CVSS score of 4.8/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-21029?

CVE-2021-21029 affects the following packages: magento/community-edition (Packagist), magento/community-edition (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2021-21029?

Update magento/community-edition to 2.3.6-p1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21029 is resolved across your whole dependency graph.

How do I detect CVE-2021-21029 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for magento/community-edition, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-21029 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2021-21029 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-21029 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-21029?

CVE-2021-21029 has an EPSS (Exploit Prediction Scoring System) score of 84.6%, placing it in the 100th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2021-21029?

CVE-2021-21029 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2021-21029 published, and has it been updated?

CVE-2021-21029 was published on February 11, 2021 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘

🐘 Packagist

Not in CISA KEV

MEDIUM severity

CVE-2021-21029 — community-edition

MEDIUMFix: magento/magento2@a2eb7e2

CVE-2021-21029 is a medium-severity (CVSS 4.8) Cross-site Scripting (XSS) vulnerability in magento/community-edition. EPSS puts its 30-day exploitation probability at 84.6% (100th percentile). A fix is available for magento/community-edition — see the affected versions and patch details below.

Magento Reflected Cross-site Scripting vulnerability via 'file' parameter

Also known asBIT-magento-2021-21029GHSA-jwxh-wj79-ccm6

Published

Feb 11, 2021

Updated

Oct 24, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Oct 29, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

84.6%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

🐘magento/community-edition🐘magento/community-edition

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Magento versions 2.4.1 (and earlier), 2.4.0-p1 (and earlier) and 2.3.6 (and earlier) are affected by a Reflected Cross-site Scripting vulnerability via 'file' parameter. Successful exploitation could lead to arbitrary JavaScript execution in the victim's browser. Access to the admin console is required for successful exploitation.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`magento/community-edition`	all versions	2.3.6-p1`composer require magento/community-edition:^2.3.6-p1`
🐘Packagist	`magento/community-edition`	≥ 2.4.0&&< 2.4.2	2.4.2`composer require magento/community-edition:^2.4.2`

Affected Products

1 product · 10 configurations

Application

magentomagento

< 2.3.6

3 versions

2.3.62.4.02.4.1

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for magento/community-edition, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update magento/community-edition to 2.3.6-p1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21029 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-21029 in your dependencies?

Find it across Packagist, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

4.8/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N

CWE Classification

CWE-79Cross-site Scripting (XSS)

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

OpenSSF Scorecard

Package health score

magento2

6.2/10

Maintained10/10

Code-Review1/10

Branch-ProtectionN/A

Assessed Oct 26, 2026

Timeline

Disclosed

Feb 11, 2021

Last updated

Oct 24, 2026

Identifiers

CVE-2021-21029

GHSA-jwxh-wj79-ccm6

BIT-magento-2021-21029

References

Advisoryhelpx.adobe.com · apsb21 08 Advisorynvd.nist.gov · CVE 2021 21029 Webgithub.com · a2eb7e29ea92a8bbc86c3b6b81b59d8533088497 Webgithub.com · a349e022c9ae070e7da262021f9ef182105aa00b Packagegithub.com · magento2

Related vulnerabilities

This CVE is medium severity; 8 of 8 other CVEs affecting magento/community-edition are rated as high or higher (top: critical).

CVE-2025-54264CVE-2025-54263CVE-2025-54266CVE-2025-54267CVE-2025-54265CVE-2025-54236CVE-2025-49555CVE-2025-49556

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 24, 2026