CVE-2026-19912: Kaltura HTML5 Video Player, HTML5 Library

Critical severity, CVSS 9.8. EPSS: 1% chance of exploitation in the next 30 days.

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.

Affected products

• Kaltura Kaltura HTML5 Video Player, HTML5 Library: up to and including v2.103; version 2.45 only

Published 2026-08-25. Last modified 2026-09-03.