How severe is CVE-2021-20717?

CVE-2021-20717 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-20717?

CVE-2021-20717 affects the following packages: ec-cube/ec-cube (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2021-20717?

The records we use list no patched version of ec-cube/ec-cube for CVE-2021-20717. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.

How do I detect CVE-2021-20717 in my Packagist dependencies?

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

How do I mitigate CVE-2021-20717 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-2021-20717 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-20717 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-2021-20717?

CVE-2021-20717 has an EPSS (Exploit Prediction Scoring System) score of 2.3%, placing it in the 83th 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. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-20717?

CVE-2021-20717 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-2021-20717 published, and has it been updated?

CVE-2021-20717 was published on May 10, 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-2021-20717 — ec-cube

MEDIUM

CVE-2021-20717 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in ec-cube/ec-cube. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.

EC-CUBE Cross-site scripting vulnerability

Also known asGHSA-c8mx-43cq-993w

Published

May 10, 2021

Updated

Oct 24, 2026

Affected

1 pkg

Patched

See advisory

Exploits

None indexed

Exploitation data as of Nov 1, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

2.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs83th percentile — riskier than 83% 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

1 pkg affected

🐘ec-cube/ec-cube

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

Cross-site scripting vulnerability in EC-CUBE 4.0.0 to 4.0.5 allows a remote attacker to inject a specially crafted script in the specific input field of the EC web site which is created using EC-CUBE. As a result, it may lead to an arbitrary script execution on the administrator's web browser.

Affected Packages

1 total

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`ec-cube/ec-cube`	≥ 4.0.0	No fix

Affected Products

1 product · 1 configurations

Application

ec-cubeec-cube

≥ 4.0.0 && < 4.0.5

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ec-cube/ec-cube, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
The records we use list no patched version of ec-cube/ec-cube for CVE-2021-20717. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.
Mitigate without a patch
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-2021-20717 in your dependencies?

Find it across Packagist, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

6.1/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/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

ec-cube

6.6/10

Maintained10/10

Code-Review10/10

Branch-ProtectionN/A

Assessed Oct 26, 2026

Timeline

Disclosed

May 10, 2021

Last updated

Oct 24, 2026

Identifiers

CVE-2021-20717

GHSA-c8mx-43cq-993w

References

Advisoryjvn.jp · index Advisorynvd.nist.gov · CVE 2021 20717 Fixec-cube.net · detail Fixec-cube.net · detail Packagegithub.com · ec cube

Related vulnerabilities

This CVE is medium severity; 7 of 8 other CVEs affecting ec-cube/ec-cube are rated as high or higher (top: high).

GHSA-7rhv-h82h-vpjhCVE-2022-38975CVE-2022-40199CVE-2020-5680CVE-2020-5590CVE-2021-20842CVE-2021-20751CVE-2020-5679

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 24, 2026