Cross-site Scripting (XSS) Affecting lxml package, versions <4.6.2-1


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
3.93% (89th percentile)

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  • Snyk IDSNYK-ECHOLATEST-LXML-19222756
  • published23 Aug 2026
  • disclosed3 Dec 2020

Introduced: 3 Dec 2020

CVE-2020-27783  (opens in a new tab)
CWE-79  (opens in a new tab)

How to fix?

Upgrade Echo:latest lxml to version 4.6.2-1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream lxml package and not the lxml package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

A XSS vulnerability was discovered in python-lxml's clean module. The module's parser didn't properly imitate browsers, which caused different behaviors between the sanitizer and the user's page. A remote attacker could exploit this flaw to run arbitrary HTML/JS code.

CVSS Base Scores

version 3.1