CVE-2022-0776 is a medium-severity (CVSS 5.3) Cross-site Scripting (XSS) vulnerability in reveal.js. 1 public exploit reference exists, so weaponization risk is real. A fix is available for reveal.js — see the affected versions and patch details below.
Cross-site Scripting (XSS) - DOM in hakimel/reveal.js
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2022-0776 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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.
reveal.jsnpmDescription
The onmessage event listener in /plugin/notes/speaker-view.html does not check the origin of postMessage before adding the content to the webpage. The vulnerable code allows any origin to postMessage on the browser window and feeds attacker's input to parts using which attacker can execute arbitrary javascript code on victim's browser window hosting reveal.js
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | reveal.js | all versions | 4.3.0npm install reveal.js@4.3.0 |
Affected Products
reveal.jsrevealjsResearch 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 reveal.js, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update reveal.js to 4.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-0776 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.
How to detect CVE-2022-0776
A community-maintained Nuclei template exists for this CVE. You can scan for it directly:
nuclei -id cve-2022-0776 -u https://target- Template
- RevealJS postMessage <4.3.0 - Cross-Site Scripting
- Severity
- medium
- Impact
- Successful exploitation of this vulnerability could allow an attacker to execute arbitrary JavaScript code in the context of the victim's browser, leading to potential data theft, session hijacking, or defacement of the affected website.
- Remediation
- Upgrade to RevealJS postMessage version 4.3.0 or later to mitigate this vulnerability.
Template by ProjectDiscovery nuclei-templates (LogicalHunter), MIT licensed. View the full template. Scan only systems you are authorised to test.
Frequently Asked Questions
Is CVE-2022-0776 in your dependencies?
Find it across npm, including transitive dependencies.