CVE-2026-27210
Fix: mpetroff/pannellum@9391ef8CVE-2026-27210 is a Cross-site Scripting (XSS) vulnerability in pannellum. O3 Security confirms whether CVE-2026-27210 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Pannellum has a XSS vulnerability in hot spot attributes
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
pannellumnpmDescription
Pannellum is a lightweight, free, and open source panorama viewer for the web. In versions 3.5.0 through 2.5.6, the hot spot attributes configuration property allowed any attribute to be set, including HTML event handler attributes, allowing for potential XSS attacks. This affects websites hosting the standalone viewer HTML file and any other use of untrusted JSON config files (bypassing the protections of the escapeHTML parameter). As certain events fire without any additional user interaction, visiting a standalone viewer URL that points to a malicious config file — without additional user interaction — is sufficient to trigger the vulnerability and execute arbitrary JavaScript code, which can, for example, replace the contents of the page with arbitrary content and make it appear to be hosted by the website hosting the standalone viewer HTML file. This issue has been fixed in version 2.5.7. To workaround, setting the Content-Security-Policy header to script-src-attr 'none' will block execution of inline event handlers, mitigating this vulnerability. Don't host pannellum.htm on a domain that shares cookies with user authentication to mitigate XSS risk.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | pannellum | ≥ 2.5.0&&< 2.5.7 | 2.5.7 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pannellum. 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 pannellum to 2.5.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-27210 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 CVE-2026-27210 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 CVE-2026-27210. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-27210 in your dependencies?
O3 detects CVE-2026-27210 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.