What is CVE-2020-7642?

CVE-2020-7642 is a medium-severity vulnerability in Lazysizes Project, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2020-04-22.

How severe is CVE-2020-7642?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Lazysizes Project

CVE-2020-7642

lazysizes through 5.2.0 allows execution of malicious JavaScript. The following attributes are not sanitized by the video-embed plugin: data-vimeo, data-vimeoparams, data-youtube and data-ytparams which can be abused to inject malicious JavaScript.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2020-04-22 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.009 (57.9th percentile), scored 2026-10-03.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 58th percentile — 57.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000

Affected products

Lazysizes Project
Lazysizes — versions All versions including 5.2.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

snyk.io/vuln/SNYK-JS-LAZYSIZES-567144 (Exploit, Third Party Advisory)
github.com/aFarkas/lazysizes/commit/3720ab8262552d4e063a38d8492f9490a231fd48 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2020-7642?: CVE-2020-7642 is a medium-severity vulnerability in Lazysizes Project, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2020-04-22.
How severe is CVE-2020-7642?: Medium severity. CVSS v3 base score is 5.4 out of 10.