{"id":"UBUNTU-CVE-2026-71488","details":"league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 0.6.0 until 2.9.0, specially crafted Markdown lines can cause the parser to have quadratic time complexity when converting, because several parsing paths repeatedly rescan growing portions of a line to translate between character positions and byte positions, and the Autolink extension can also copy and validate the remaining line at every URL-like prefix, allowing an attacker who can submit Markdown for conversion to consume disproportionate CPU time with a comparatively small request. This issue is fixed in 2.9.0.","modified":"2026-08-13T00:14:08Z","published":"2026-08-06T22:18:00Z","upstream":["CVE-2026-71488"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-71488"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-71488"},{"type":"REPORT","url":"https://github.com/thephpleague/commonmark/commit/a6ef6cdc308dfa39a34239c35818e75892a0e6a8"},{"type":"REPORT","url":"https://github.com/thephpleague/commonmark/commit/a70979ea0d7d3377bd7127536748454a922bf5eb"},{"type":"REPORT","url":"https://github.com/thephpleague/commonmark/commit/c97b02e5e652b992033b93ba5d6182f706343fc6"},{"type":"REPORT","url":"https://github.com/thephpleague/commonmark/releases/tag/2.9.0"},{"type":"REPORT","url":"https://github.com/thephpleague/commonmark/security/advisories/GHSA-2q4p-g7hv-5rgv"}],"affected":[{"package":{"name":"markdown","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/markdown?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0.1-7","1.0.1-8"],"ecosystem_specific":{"binaries":[{"binary_version":"1.0.1-8","binary_name":"markdown"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71488.json"}},{"package":{"name":"markdown","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/markdown?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0.1-9","1.0.1-10"],"ecosystem_specific":{"binaries":[{"binary_version":"1.0.1-10","binary_name":"markdown"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71488.json"}},{"package":{"name":"markdown","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/markdown?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0.1-10"],"ecosystem_specific":{"binaries":[{"binary_name":"markdown","binary_version":"1.0.1-10"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71488.json"}},{"package":{"name":"commonmark","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/commonmark?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.9.1-3"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-commonmark","binary_version":"0.9.1-3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71488.json"}},{"package":{"name":"markdown","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/markdown?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0.1-10.1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.0.1-10.1","binary_name":"markdown"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71488.json"}},{"package":{"name":"commonmark","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/commonmark?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.9.1-4","0.9.1-5"],"ecosystem_specific":{"binaries":[{"binary_version":"0.9.1-5","binary_name":"python3-commonmark"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71488.json"}},{"package":{"name":"markdown","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/markdown?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0.1-12"],"ecosystem_specific":{"binaries":[{"binary_name":"markdown","binary_version":"1.0.1-12"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71488.json"}},{"package":{"name":"commonmark","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/commonmark?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.9.1-8","0.9.1-8build1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-commonmark","binary_version":"0.9.1-8build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71488.json"}},{"package":{"name":"markdown","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/markdown?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0.1-14"],"ecosystem_specific":{"binaries":[{"binary_version":"1.0.1-14","binary_name":"markdown"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-71488.json"}}],"schema_version":"1.9.0","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"}]}