What is CVE-2021-20734?

CVE-2021-20734 is a medium-severity vulnerability in Collne Inc. Welcart E-Commerce, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-06-22.

How severe is CVE-2021-20734?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Is CVE-2021-20734 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

XSS in Collne Inc. Welcart E-Commerce

CVE-2021-20734

Cross-site scripting vulnerability in Welcart e-Commerce versions prior to 2.2.4 allows remote attackers to inject arbitrary script or HTML via unspecified vectors.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-06-22 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.010 (62.7th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 63rd percentile — 62.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000

Affected products

Collne Inc. Welcart E-Commerce — versions versions prior to 2.2.4
Welcart E-Commerce — versions 1.5.2

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

References

www.welcart.com/archives/14039.html (Vendor Advisory)
jvn.jp/en/jp/JVN70566757/index.html (Third Party Advisory)

Frequently asked questions

What is CVE-2021-20734?: CVE-2021-20734 is a medium-severity vulnerability in Collne Inc. Welcart E-Commerce, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2021-06-22.
How severe is CVE-2021-20734?: Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2021-20734 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.