CVE-2021-23342: Cross-site Scripting (XSS)

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.7% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-02-19 · updated 2026-06-17
Weakness: CWE-79

Description

This affects the package docsify before 4.12.0. It is possible to bypass the remediation done by CVE-2020-7680 and execute malicious JavaScript through the following methods 1) When parsing HTML from remote URLs, the HTML code on the main page is sanitized, but this sanitization is not taking place in the sidebar. 2) The isURL external check can be bypassed by inserting more “////” characters

Affected products

docsify: before 4.12.0 — fixed in 4.12.0

How to fix

Upgrade to a fixed version: docsify 4.12.0. Check the vendor advisory for mitigations.

References

http://packetstormsecurity.com/files/161495/docsify-4.11.6-Cross-Site-Scripting.html
http://seclists.org/fulldisclosure/2021/Feb/71
https://github.com/docsifyjs/docsify/commit/ff2a66f12752471277fe81a64ad6c4b2c08111fe
https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1076593
https://snyk.io/vuln/SNYK-JS-DOCSIFY-1066017
http://packetstormsecurity.com/files/161495/docsify-4.11.6-Cross-Site-Scripting.html
http://seclists.org/fulldisclosure/2021/Feb/71
https://github.com/docsifyjs/docsify/commit/ff2a66f12752471277fe81a64ad6c4b2c08111fe
https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1076593
https://snyk.io/vuln/SNYK-JS-DOCSIFY-1066017

Get alerted when CVE-2021-23342 or the next vulnerability affects your stack