Denial of Service in Discourse

Discourse is an open source discussion platform. In versions prior to 2.8.1 in the `stable` branch, 2.9.0.beta2 in the `beta` branch, and 2.9.0.beta2 in the `tests-passed` branch, users can trigger a Denial of Service attack by posting a streaming URL. Parsing Oneboxes in the background job trigger an infinite loop, which cause memory leaks. This issue is patched in version 2.8.1 of the `stable` branch, 2.9.0.beta2 of the `beta` branch, and 2.9.0.beta2 of the `tests-passed` branch. As a workaround, disable onebox in admin panel completely or specify allow list of domains that will be oneboxed.