How severe is CVE-2020-6578?

CVE-2020-6578 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-2020-6578?

CVE-2020-6578 affects the following packages: zencart/zencart (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2020-6578?

Update zencart/zencart to 1.5.7a or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-6578 is resolved across your whole dependency graph.

How do I detect CVE-2020-6578 in my Packagist dependencies?

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

How do I mitigate CVE-2020-6578 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-2020-6578 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2020-6578, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2020-6578?

CVE-2020-6578 has an EPSS (Exploit Prediction Scoring System) score of 0.8%, placing it in the 58th 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-2020-6578?

CVE-2020-6578 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-2020-6578 published, and has it been updated?

CVE-2020-6578 was published on March 19, 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-2020-6578 — zencart

MEDIUMFix: zencart/zencart@aa11e1e

CVE-2020-6578 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in zencart/zencart. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for zencart/zencart — see the affected versions and patch details below.

Reflected XSS in Zen Cart before 1.5.7a

Also known asGHSA-wxxx-2x6v-979f

Published

Mar 19, 2021

Updated

Oct 24, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

1 known

Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.8%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs58th percentile — riskier than 58% 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

🐘zencart/zencart

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

Zen Cart 1.5.6d allows reflected XSS via the main_page parameter to includes/templates/template_default/common/tpl_main_page.php or includes/templates/responsive_classic/common/tpl_main_page.php.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`zencart/zencart`	all versions	1.5.7a`composer require zencart/zencart:^1.5.7a`

Affected Products

1 product · 1 configurations

Application

zen cartzen-cart

1 version

1.5.6d

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Zen Cart 1.5.6d allows reflected XSS via the main_page parameter to incl…

herolab.usd.deNVDMar 2021

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for zencart/zencart, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update zencart/zencart to 1.5.7a or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-6578 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

Zen Cart 1.5.6d allows reflected XSS via the main_page parameter to includes/templates/template_default/common/tpl_main_page.php or includes/templates/responsive_classic/common/tpl_main_page.php.

O3 Security · Impact-Aware SCA

Is CVE-2020-6578 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 or Metasploit module yet. 1 public proof-of-concept reference is listed on this page.

OpenSSF Scorecard

Package health score

zencart

4.7/10

Maintained10/10

Code-Review3/10

Branch-ProtectionN/A

Assessed Oct 19, 2026

Timeline

Disclosed

Mar 19, 2021

First exploit

Mar 25, 2021

6 days after disclosure — rapid exploitation

Last updated

Oct 24, 2026

Identifiers

CVE-2020-6578

GHSA-wxxx-2x6v-979f

References

Advisoryherolab.usd.de · security advisories Advisorynvd.nist.gov · CVE 2020 6578 Webgithub.com · aa11e1e06c11b8a2940299a4bec0ac3dd95a7895 Webherolab.usd.de · usd 2019 0069 Evidenceherolab.usd.de · usd 2019 0069

Related vulnerabilities

Also affects zencart/zencart

This CVE is medium severity; 2 of 2 other CVEs affecting zencart/zencart are rated as high or higher (top: high).

CVE-2021-3291CVE-2017-11675

Same weakness: CWE-79

This CVE is medium severity; 6 of 6 other CVEs with CWE-79 are rated as high or higher (top: critical).

CVE-2026-113787CVE-2026-44267CVE-2026-96632CVE-2026-9086CVE-2026-118246CVE-2026-118251Browse all CWE-79

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 24, 2026