CoBlocks < 3.1.13 - Editor+ Stored XSS

The Page Builder Gutenberg Blocks WordPress plugin before 3.1.13 does not escape the content of post embed via one of its block, which could allow users with the capability to publish posts (editor and admin by default) to perform Stored Cross-Site Scripting attacks even when the unfiltered_html capability is disallowed (for example in multisite setup)