CVE-2026-27210 — pannellum
Fix: mpetroff/pannellum@9391ef8CVE-2026-27210 is a Cross-site Scripting (XSS) vulnerability in pannellum. A fix is available for pannellum — see the affected versions and patch details below.
Pannellum has a XSS vulnerability in hot spot attributes
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-27210.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
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.
pannellumnpmDescription
Impact
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.
Patches
This has been fixed both in v2.5.7 and in the current development branch.
Workarounds
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.
Acknowledgments
Reported both by luminary (@lumin9ry), Visvge (@Sicclord1 / @Visvge), and sutol (@0x5a6163 / @SUT0L) and by another researcher who wishes not to be named at this time.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | pannellum | ≥ 2.5.0&&< 2.5.7 | 2.5.7npm install pannellum@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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-27210 can be triaged on real exposure rather than presence alone.
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 Security finds CVE-2026-27210 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.