PrivateBin up to 2.0.4 JSON-LD Output lib/Controller.php Controller::_jsonld REQUEST_URI cross site scripting

Summaryinfo

A vulnerability, which was classified as problematic, was found in PrivateBin up to 2.0.4. This impacts the function Controller::_jsonld of the file lib/Controller.php of the component JSON-LD Output. Such manipulation of the argument REQUEST_URI leads to cross site scripting. This vulnerability is traded as CVE-2026-55891. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in PrivateBin up to 2.0.4. It has been rated as problematic. Affected by this issue is the function Controller::_jsonld of the file lib/Controller.php of the component JSON-LD Output. The manipulation of the argument REQUEST_URI with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to 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. Impacted is integrity. CVE summarizes:

PrivateBin is an online pastebin where the server has zero knowledge of pasted data. Prior to 2.0.5, Request::getRequestUri() in lib/Request.php passes $_SERVER['REQUEST_URI'] through FILTER_SANITIZE_URL, which does not remove quotation marks, angle brackets, or apostrophes, and Controller::_init() stores the attacker-controlled value in Controller::$_urlBase. Controller::_jsonld() in lib/Controller.php then uses str_replace() to insert that value without JSON escaping into js/types.jsonld, js/paste.jsonld, and the other JSON-LD templates used by /?jsonld= and /?pasteid. A raw quotation mark delivered by an HTTP client, proxy, or structured-data crawler that does not normalize the request target can break out of the JSON string and inject arbitrary key-value data into a CORS-open application/ld+json response. The jsonld branch in Controller::__construct() returns before _setCacheHeaders(), so the response also lacks X-Content-Type-Options: nosniff, Content Security Policy, X-Frame-Options, and Referrer-Policy. Direct script execution was not demonstrated, but manipulated responses can affect structured-data consumers or combine with less strict clients. This issue is fixed in version 2.0.5.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-55891 since 06/17/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. 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:lib/Controller.php it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 2.0.5 eliminates this vulnerability.

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Productinfo

Name

• PrivateBin

Version

• 2.0.0
• 2.0.1
• 2.0.2
• 2.0.3
• 2.0.4

Website

• Product: https://github.com/PrivateBin/PrivateBin/

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