There is 1 open security issue in buster.
1 issue left for the package maintainer to handle:
The table extension in GitHub Flavored Markdown before version 0.29.0.gfm.1 takes O(n * n) time to parse certain inputs. An attacker could craft a markdown table which would take an unreasonably long time to process, causing a denial of service. This issue does not affect the upstream cmark project. The issue has been fixed in version 0.29.0.gfm.1.
You can find information about how to handle this issue in the security team's documentation.