MEDIUM
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.
https://github.com/github/cmark-gfm/commit/85d895289c5ab67f988ca659493a64abb5fec7b4
https://github.com/github/cmark-gfm/security/advisories/GHSA-7gc6-9qr5-hc85
Source: MITRE
Published: 2020-07-01
Updated: 2020-10-06
Type: CWE-20
Base Score: 4
Vector: AV:N/AC:L/Au:S/C:N/I:N/A:P
Impact Score: 2.9
Exploitability Score: 8
Severity: MEDIUM
Base Score: 6.5
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Impact Score: 3.6
Exploitability Score: 2.8
Severity: MEDIUM