CVE-2026-19912

Unknown

Published: 25/08/2026(UTC)Translated: 25/08/2026(UTC)NVD NIST

Summary

The Kaltura HTML5 player (mwEmbed / html5lib) contains an unauthenticated remote code execution vulnerability caused by unsafe data deserialization and unsanitized filesystem path construction. mwEmbedLoader.php accepts a user-controlled ServiceUrl, whose response is passed to unserialize(), and the resulting object’s fields are written to a cache path derived from attacker-supplied uiconf_id without proper path validation. An attacker can write arbitrary files into web-accessible locations and achieve code execution as the webserver user.

Risk Assessment

An attacker can take over the web server, potentially leading to full system compromise, data theft, or further attacks within the network.

Recommendation

Immediately update html5lib to a patched version. If not possible, disable or restrict access to mwEmbedLoader.php and apply measures such as WAF and monitoring for unusual requests.

Other vulnerabilities in Kaltura HTML5 player (html5lib)

CVE-2026-19913High
The Kaltura HTML5 player (mwEmbed / html5lib) contains a local file disclosure vulnerability due to improper validation of the ServiceUrl parameter in mwEmbedLoader.php. This parameter is used as the base URL for a backend request and accepts non-HTTP schemes such as file://. When an exception or error occurs, the response is subsequently deserialized and its raw contents are reflected to the client in an error message; this enables an unauthenticated, remote attacker to read any arbitrary internal file reachable by the server.

Original NVD description (English source)

The Kaltura HTML5 player (mwEmbed / html5lib) contains an unauthenticated remote code execution vulnerability caused by unsafe data deserialization and unsanitized filesystem path construction. mwEmbedLoader.php accepts a user‑controlled ServiceUrl, whose response is passed to unserialize(), and the resulting object’s fields are written to a cache path derived from attacker‑supplied uiconf_id without proper path validation. An attacker can write arbitrary files into web‑accessible locations and achieve code execution as the webserver user. Affected versions include html5lib v2.45, v2.103 and earlier, and other v2.x releases exposing the vulnerable endpoint.