GHSA-49rv-g7w5-m8xx is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in @novnc/novnc. 3 public exploit references exist, so weaponization risk is real. O3 Security confirms whether GHSA-49rv-g7w5-m8xx is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Cross-Site Scripting in @novnc/novnc
Real-World Exposure
@novnc/novncReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
Versions of @novnc/novnc prior to 0.6.2 are vulnerable to Cross-Site Scripting (XSS). The package fails to validate input from the remote VNC server such as the VNC server name. This allows an attacker in control of the remote server to execute arbitrary JavaScript in the noVNC web page. It affects any users of include/ui.js and users of vnc_auto.html and vnc.html.
Recommendation
Upgrade to version 0.6.2 or later.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @novnc/novnc | all versions | 0.6.2 |
Research 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 @novnc/novnc. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update @novnc/novnc to 0.6.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-49rv-g7w5-m8xx is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-49rv-g7w5-m8xx is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-49rv-g7w5-m8xx. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Frequently Asked Questions
Is GHSA-49rv-g7w5-m8xx in your dependencies?
O3 detects GHSA-49rv-g7w5-m8xx across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.