Describe CVE-2021-3866.
What is CVE-2021-3866?
Cross-site Scripting (XSS) - Stored in GitHub repository zulip/zulip more than and including 44f935695d452cc3fb16845a0c6af710438b153d and prior to 3eb2791c3e9695f7d37ffe84e0c2184fae665cb6..