Vulnerability in Discourse Discourse-Footnote
CVE-2021-43827
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.
EPSS: 0.008 (53.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L.
Affected products
- Discourse Discourse-footnote — versions < 0.2
- Discourse Discourse_footnote
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Third Party Advisory)
- security-advisories@github.com (Patch, Third Party Advisory, x_refsource_MISC)
Frequently asked questions
- What is CVE-2021-43827?
- CVE-2021-43827 is a medium-severity vulnerability in Discourse Discourse-Footnote, classified under Improper Handling of Exceptional Conditions. CVSS score: 4.3/10. Published 2021-12-14.
- How severe is CVE-2021-43827?
- Medium severity. CVSS v3 base score is 4.3 out of 10.