Vulnerability · Published Dec 14, 2021 · Assigned by GitHub_M
CVE-2021-43827Inline footnotes wrapped in <a> tags can cause errors in discourse-footnotes
Medium 4.3
In plain English
A medium-severity security flaw in discourse-footnote from discourse. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 58% of all known vulnerabilities).
Official description
discourse-footnote is a library providing footnotes for posts in Discourse. ### Impact When posting an inline footnote wrapped in `<a>` tags (e.g. `<a>^[footnote]</a>`, the resulting rendered HTML would include a nested `<a>`, which is stripped by Nokogiri because it is not valid. This then caused a javascript error on topic pages because we were looking for an `<a>` element inside the footnote reference span and getting its ID, and because it did not exist we got a null reference error in javascript. Users are advised to update to version 0.2. As a workaround editing offending posts from the rails console or the database console for self-hosters, or disabling the plugin in the admin panel can mitigate this issue.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| discourse | discourse-footnote | < 0.2 |
Weakness: CWE-755 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L