{"id":"UBUNTU-CVE-2021-3156","details":"Sudo before 1.9.5p2 contains an off-by-one error that can result in a heap-based buffer overflow, which allows privilege escalation to root via \"sudoedit -s\" and a command-line argument that ends with a single backslash character.","modified":"2026-02-04T03:55:02.249874Z","published":"2021-01-26T18:00:00Z","related":["USN-4705-1","USN-4705-2"],"upstream":["CVE-2021-3156"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-3156"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-4705-1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-4705-2"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-3156"},{"type":"REPORT","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog"}],"affected":[{"package":{"name":"sudo","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/sudo@1.8.9p5-1ubuntu1.5+esm6?arch=source&distro=trusty/esm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.8.9p5-1ubuntu1.5+esm6"}]}],"versions":["1.8.6p3-0ubuntu3","1.8.8-2ubuntu1","1.8.8-2ubuntu2","1.8.9p4-1ubuntu1","1.8.9p4-1ubuntu2","1.8.9p5-1ubuntu1","1.8.9p5-1ubuntu1.1","1.8.9p5-1ubuntu1.2","1.8.9p5-1ubuntu1.3","1.8.9p5-1ubuntu1.4","1.8.9p5-1ubuntu1.5+esm1","1.8.9p5-1ubuntu1.5+esm2","1.8.9p5-1ubuntu1.5+esm3","1.8.9p5-1ubuntu1.5+esm5"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro","binaries":[{"binary_version":"1.8.9p5-1ubuntu1.5+esm6","binary_name":"sudo"},{"binary_version":"1.8.9p5-1ubuntu1.5+esm6","binary_name":"sudo-ldap"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3156.json"}},{"package":{"name":"sudo","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/sudo@1.8.16-0ubuntu1.10?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.8.16-0ubuntu1.10"}]}],"versions":["1.8.12-1ubuntu3","1.8.16-0ubuntu1","1.8.16-0ubuntu1.1","1.8.16-0ubuntu1.2","1.8.16-0ubuntu1.3","1.8.16-0ubuntu1.4","1.8.16-0ubuntu1.5","1.8.16-0ubuntu1.6","1.8.16-0ubuntu1.7","1.8.16-0ubuntu1.8","1.8.16-0ubuntu1.9"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_version":"1.8.16-0ubuntu1.10","binary_name":"sudo"},{"binary_version":"1.8.16-0ubuntu1.10","binary_name":"sudo-ldap"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3156.json"}},{"package":{"name":"sudo","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/sudo@1.8.21p2-3ubuntu1.4?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.8.21p2-3ubuntu1.4"}]}],"versions":["1.8.20p2-1ubuntu1","1.8.21p2-2ubuntu1","1.8.21p2-3ubuntu1","1.8.21p2-3ubuntu1.1","1.8.21p2-3ubuntu1.2","1.8.21p2-3ubuntu1.3"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_version":"1.8.21p2-3ubuntu1.4","binary_name":"sudo"},{"binary_version":"1.8.21p2-3ubuntu1.4","binary_name":"sudo-ldap"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3156.json"}},{"package":{"name":"sudo","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/sudo@1.8.31-1ubuntu1.2?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.8.31-1ubuntu1.2"}]}],"versions":["1.8.27-1ubuntu4","1.8.29-1ubuntu1","1.8.31-1ubuntu1","1.8.31-1ubuntu1.1"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_version":"1.8.31-1ubuntu1.2","binary_name":"sudo"},{"binary_version":"1.8.31-1ubuntu1.2","binary_name":"sudo-ldap"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-3156.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},{"type":"Ubuntu","score":"high"}]}