Discourse is an open-source discussion platform. Prior to version 3.2.3 on the `stable` branch and version 3.3.0.beta3 on the `tests-passed` branch, an attacker can execute arbitrary JavaScript on users’ browsers by posting a specific URL containing maliciously crafted meta tags. This issue only affects sites with Content Security Polic (CSP) disabled. The problem has been patched in version 3.2.3 on the `stable` branch and version 3.3.0.beta3 on the `tests-passed` branch. As a workaround, ensure CSP is enabled on the forum.

GitHub, Inc. AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:L

GitHub, Inc. CWE-79

GitHub, Inc. https://github.com/discourse/discourse/commit/26aef0c288839378b9de5819e96eac8cf4ea60fd [No types assigned]

GitHub, Inc. https://github.com/discourse/discourse/commit/311b737c910cf0a69f61e1b8bc0b78374b6619d2 [No types assigned]

GitHub, Inc. https://github.com/discourse/discourse/security/advisories/GHSA-5chg-hm8c-wc58 [No types assigned]