mpetroff pannellum up to 2.5.6 pannellum.htm escapeHTML cross site scripting

Summaryinfo

A vulnerability categorized as problematic has been discovered in mpetroff pannellum up to 2.5.6. Affected by this vulnerability is an unknown functionality of the file pannellum.htm. The manipulation of the argument escapeHTML results in cross site scripting. This vulnerability is reported as CVE-2026-27210. The attack can be launched remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in mpetroff pannellum up to 2.5.6. Affected is an unknown functionality of the file pannellum.htm. The manipulation of the argument escapeHTML with an unknown input leads to a cross site scripting vulnerability. CWE is classifying the issue as CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. This is going to have an impact on integrity. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-27210 since 02/18/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.007.

By approaching the search of inurl:pannellum.htm it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 2.5.7 eliminates this vulnerability. Applying the patch 9391ef8da6a6a98c6a9f8c97f101adb900523681 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

• mpetroff

Name

• pannellum

Version

• 2.5.0
• 2.5.1
• 2.5.2
• 2.5.3
• 2.5.4
• 2.5.5
• 2.5.6

License

• open-source

Website

• Product: https://github.com/mpetroff/pannellum/

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