{"id":"UBUNTU-CVE-2021-33912","details":"libspf2 before 1.2.11 has a four-byte heap-based buffer overflow that might allow remote attackers to execute arbitrary code (via an unauthenticated e-mail message from anywhere on the Internet) with a crafted SPF DNS record, because of incorrect sprintf usage in SPF_record_expand_data in spf_expand.c. The vulnerable code may be part of the supply chain of a site's e-mail infrastructure (e.g., with additional configuration, Exim can use libspf2; the Postfix web site links to unofficial patches for use of libspf2 with Postfix; older versions of spfquery relied on libspf2) but most often is not.","modified":"2026-04-22T14:48:08.015233Z","published":"2022-01-19T18:15:00Z","related":["USN-6584-1","USN-6584-2"],"upstream":["CVE-2021-33912"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-33912"},{"type":"REPORT","url":"https://github.com/shevek/libspf2/commit/28faf4624a6a371b11afdb9820078d3b0ee3803d"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-6584-1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-6584-2"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-33912"}],"affected":[{"package":{"name":"libspf2","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/libspf2@1.2.10-6ubuntu0.1~esm2?arch=source&distro=esm-apps/xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.10-6ubuntu0.1~esm2"}]}],"versions":["1.2.10-6","1.2.10-6build1","1.2.10-6ubuntu0.1~esm1"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro","binaries":[{"binary_name":"libmail-spf-xs-perl","binary_version":"1.2.10-6ubuntu0.1~esm2"},{"binary_version":"1.2.10-6ubuntu0.1~esm2","binary_name":"libspf2-2"},{"binary_name":"spfquery","binary_version":"1.2.10-6ubuntu0.1~esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-33912.json"}},{"package":{"name":"libspf2","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/libspf2@1.2.10-7ubuntu0.18.04.1~esm1?arch=source&distro=esm-apps/bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.10-7ubuntu0.18.04.1~esm1"}]}],"versions":["1.2.10-7build2"],"ecosystem_specific":{"binaries":[{"binary_name":"libmail-spf-xs-perl","binary_version":"1.2.10-7ubuntu0.18.04.1~esm1"},{"binary_name":"libspf2-2","binary_version":"1.2.10-7ubuntu0.18.04.1~esm1"},{"binary_name":"spfquery","binary_version":"1.2.10-7ubuntu0.18.04.1~esm1"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-33912.json"}},{"package":{"name":"libspf2","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/libspf2@1.2.10-7+deb9u2build0.20.04.1?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.10-7+deb9u2build0.20.04.1"}]}],"versions":["1.2.10-7build3","1.2.10-7build4"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_name":"libmail-spf-xs-perl","binary_version":"1.2.10-7+deb9u2build0.20.04.1"},{"binary_name":"libspf2-2","binary_version":"1.2.10-7+deb9u2build0.20.04.1"},{"binary_name":"spfquery","binary_version":"1.2.10-7+deb9u2build0.20.04.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-33912.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:H/I:H/A:H"},{"type":"Ubuntu","score":"medium"}]}