CVE-2026-19912

Name of the Vulnerable Software and Affected Versions html5lib versions 2.x and earlier

Description The Kaltura HTML5 player (mwEmbed / html5lib) contains an unauthenticated remote code execution issue resulting from unsafe data deserialization and unsanitized filesystem path construction. The endpoint 'mwEmbedLoader.php' accepts a user-controlled ServiceUrl parameter, the response of which is processed by the unserialize() function. Subsequently, the fields of the resulting object are written to a cache path derived from the attacker-supplied uiconf id variable without proper path validation. This allows an attacker to write arbitrary files into web-accessible locations and execute code with the privileges of the webserver user.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.