{"id":"UBUNTU-CVE-2021-26813","details":"markdown2 \u003e=1.0.1.18, fixed in 2.4.0, is affected by a regular expression denial of service vulnerability. If an attacker provides a malicious string, it can make markdown2 processing difficult or delayed for an extended period of time.","modified":"2026-05-20T16:04:51.282517727Z","published":"2021-03-03T16:15:00Z","upstream":["CVE-2021-26813"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-26813"},{"type":"REPORT","url":"https://github.com/trentm/python-markdown2/pull/387"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-26813"}],"affected":[{"package":{"name":"python-markdown2","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/python-markdown2?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.3.7-2"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-markdown2","binary_version":"2.3.7-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-26813.json"}},{"package":{"name":"python-markdown2","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/python-markdown2?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.3.10-1.1","2.4.1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-markdown2","binary_version":"2.4.1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-26813.json"}},{"package":{"name":"python-markdown2","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/python-markdown2?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.4.1-1","2.4.11-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-markdown2","binary_version":"2.4.11-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-26813.json"}},{"package":{"name":"python-markdown2","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/python-markdown2?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.4.11-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-markdown2","binary_version":"2.4.11-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-26813.json"}},{"package":{"name":"python-markdown2","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/python-markdown2?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.4.11-1","2.5.4-2","2.5.4-3"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-markdown2","binary_version":"2.5.4-3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-26813.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}