Summary
Pannellum has a XSS vulnerability in hot spot attributes
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.
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.
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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This has been fixed both in v2.5.7 and in the current development branch.
Frequently Asked Questions
- What is CVE-2026-27210? CVE-2026-27210 is a medium-severity cross-site scripting (XSS) vulnerability in pannellum (npm), affecting versions >= 2.5.0, < 2.5.7. It is fixed in 2.5.7. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- Which versions of pannellum are affected by CVE-2026-27210? pannellum (npm) versions >= 2.5.0, < 2.5.7 is affected.
- Is there a fix for CVE-2026-27210? Yes. CVE-2026-27210 is fixed in 2.5.7. Upgrade to this version or later.
- Is CVE-2026-27210 exploitable, and should I be worried? Whether CVE-2026-27210 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-27210 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-27210? Upgrade
pannellumto 2.5.7 or later.