CVE-2021-43827 Information

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.

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

Reference

https://github.com/discourse/discourse-footnote/commit/796617e0131277011207541313522cd1946661ab https://github.com/discourse/discourse-footnote/security/advisories/GHSA-58vr-c56v-qr57

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

LOW

Base Severity

4.3