CVE-2026-19913: Input Validation
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. Affected versions include html5lib v2.45, v2.103 and earlier, and other v2.x releases exposing the vulnerable endpoint.
Affected Software
Event History
Frequently Asked Questions
Who can exploit this issue?
An unauthenticated remote attacker can exploit it if they can reach the vulnerable mwEmbedLoader.php endpoint.
What does exploitation require?
The attacker needs to supply a ServiceUrl value using a non-HTTP scheme such as file:// and trigger an exception or error so that the backend response is reflected in the error message.
What systems are affected?
Affected releases include html5lib v2.45, v2.103 and earlier, as well as other v2.x releases that expose the vulnerable endpoint.
What information could be exposed?
An attacker may read arbitrary internal files that are reachable by the server process.