CVE-2021-23342 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in docsify. 3 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for docsify — see the affected versions and patch details below.
Docsify XSS Vulnerability
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
docsifynpmDescription
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | docsify | all versions | 4.12.0npm install docsify@4.12.0 |
Affected Products
docsifydocsifyjsResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for docsify, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update docsify to 4.12.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-23342 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is CVE-2021-23342 in your dependencies?
Find it across npm, including transitive dependencies.