{"id":"CVE-2021-33913","aliases":["ALPINE-CVE-2021-33913","DEBIAN-CVE-2021-33913","DLA-2890-1","EUVD-2021-20585","GHSA-7659-433m-4fhx","UBUNTU-CVE-2021-33913","USN-6584-1","USN-6584-2"],"status":"published","title":"libspf2 before 1.2.11 has a heap-based buffer overflow that might allow remote attackers to...","description":"libspf2 before 1.2.11 has a 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 SPF_record_expand_data in spf_expand.c. The amount of overflowed data depends on the relationship between the length of an entire domain name and the length of its leftmost label. 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.","severity":{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-10","score":0.09643,"percentile":0.95528,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-787"],"published":"2022-01-19T00:00:00Z","modified":"2026-10-23T18:03:03Z","fixes":[{"ecosystem":"Alpine:v3.14","package":"libspf2","fixed_in":["1.2.11-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.15","package":"libspf2","fixed_in":["1.2.11-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.16","package":"libspf2","fixed_in":["1.2.11-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.17","package":"libspf2","fixed_in":["1.2.11-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.18","package":"libspf2","fixed_in":["1.2.11-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.19","package":"libspf2","fixed_in":["1.2.11-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.20","package":"libspf2","fixed_in":["1.2.11-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.21","package":"libspf2","fixed_in":["1.2.11-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.22","package":"libspf2","fixed_in":["1.2.11-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.23","package":"libspf2","fixed_in":["1.2.11-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.24","package":"libspf2","fixed_in":["1.2.11-r0"],"sources":["osv"]},{"ecosystem":"Debian:12","package":"libspf2","fixed_in":["1.2.10-7.1"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"libspf2","fixed_in":["1.2.10-7.1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"libspf2","fixed_in":["1.2.10-7.1"],"sources":["osv"]},{"ecosystem":"Ubuntu:Pro:16.04:LTS","package":"libspf2","fixed_in":["1.2.10-6ubuntu0.1~esm2"],"sources":["osv"]},{"ecosystem":"Ubuntu:Pro:18.04:LTS","package":"libspf2","fixed_in":["1.2.10-7ubuntu0.18.04.1~esm1"],"sources":["osv"]},{"ecosystem":"Ubuntu:20.04:LTS","package":"libspf2","fixed_in":["1.2.10-7+deb9u2build0.20.04.1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Alpine:v3.14","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.11-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.15","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.11-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.16","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.11-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.17","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.11-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.18","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.11-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.19","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.11-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.20","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.11-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.21","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.11-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.22","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.11-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.23","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.11-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.24","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.11-r0"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.10-7.1"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.10-7.1"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.10-7.1"}]}]},{"source":"osv","ecosystem":"Debian:9","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.10-7+deb9u2"}]}],"versions":["1.2.10-7","1.2.10-7+deb9u1"],"bundled":2},{"source":"osv","ecosystem":"Ubuntu:Pro:16.04:LTS","package":"libspf2","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"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.10-7ubuntu0.18.04.1~esm1"}]}],"versions":["1.2.10-7build2"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.10-7+deb9u2build0.20.04.1"}]}],"versions":["1.2.10-7build3","1.2.10-7build4"]},{"source":"osv","ecosystem":"Ubuntu:Pro:16.04:LTS","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.10-6ubuntu0.1~esm1"}]}],"versions":["1.2.10-6","1.2.10-6build1"],"bundled":3},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.10-7ubuntu0.18.04.1~esm1"}]}],"versions":["1.2.10-7build2"],"bundled":3},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"libspf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.10-7+deb9u2build0.20.04.1"}]}],"versions":["1.2.10-7build3","1.2.10-7build4"],"bundled":3},{"source":"osv","ecosystem":"Ubuntu:Pro:16.04:LTS","package":"libspf2","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"],"bundled":2}],"products":[{"vendor":"libspf2_project","product":"libspf2"}],"references":[{"url":"https://github.com/shevek/libspf2/tree/8131fe140704eaae695e76b5cd09e39bd1dd220b","tags":["x_transferred","Third Party Advisory","advisory"]},{"url":"https://nathanielbennett.com/blog/libspf2-cve-jan-2022-disclosure","tags":["x_transferred","Exploit","Third Party Advisory","evidence"]},{"url":"https://lists.debian.org/debian-lts-announce/2022/01/msg00015.html","tags":["mailing-list","x_transferred","Mailing List","Third Party Advisory","advisory"]},{"url":"https://security.gentoo.org/glsa/202401-22","tags":["vendor-advisory","x_transferred","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-33913"},{"url":"https://github.com/advisories/GHSA-7659-433m-4fhx"},{"url":"https://security.alpinelinux.org/vuln/CVE-2021-33913","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2021-33913","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2021-33913","tags":["report"]},{"url":"https://github.com/shevek/libspf2/commit/f06fef6cede4c4cb42f2c617496e6041782d7070","tags":["report"]},{"url":"https://ubuntu.com/security/notices/USN-6584-1","tags":["advisory"]},{"url":"https://ubuntu.com/security/notices/USN-6584-2","tags":["advisory"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-33913","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2021-20314","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2021-33912","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2021-33913","description":"libspf2 before 1.2.11 has a 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 SPF_record_expand_data in spf_expand.c. The amount of overflowed data depends on the relationship between the length of an entire domain name and the length of its leftmost label. 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.","status":"published","published":"2022-01-19T00:00:00Z","modified":"2024-08-04T00:05:51.79Z","updated_at":"2026-11-02T14:33:10.204494Z"}],"euvd":[{"id":"EUVD-2021-20585","description":"libspf2 before 1.2.11 has a 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 SPF_record_expand_data in spf_expand.c. The amount of overflowed data depends on the relationship between the length of an entire domain name and the length of its leftmost label. 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.","status":"published","published":"2022-01-19T00:00:00Z","modified":"2024-08-04T00:05:51Z","updated_at":"2026-11-03T03:24:33.318275Z"}],"ghsa":[{"id":"GHSA-7659-433m-4fhx","title":"libspf2 before 1.2.11 has a heap-based buffer overflow that might allow remote attackers to...","description":"libspf2 before 1.2.11 has a 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 SPF_record_expand_data in spf_expand.c. The amount of overflowed data depends on the relationship between the length of an entire domain name and the length of its leftmost label. 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.","status":"published","published":"2022-01-20T00:00:22Z","modified":"2024-01-15T18:30:18Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-787"],"updated_at":"2026-11-02T14:55:25.085259Z"}],"nvd":[{"id":"CVE-2021-33913","description":"libspf2 before 1.2.11 has a 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 SPF_record_expand_data in spf_expand.c. The amount of overflowed data depends on the relationship between the length of an entire domain name and the length of its leftmost label. 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.","status":"published","published":"2022-01-19T18:15:07.83Z","modified":"2026-06-17T03:55:22.303Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"},{"version":"2.0","score":9.3,"vector":"AV:N/AC:M/Au:N/C:C/I:C/A:C","level":"high","assessor":"primary"}],"cwes":["CWE-787"],"updated_at":"2026-11-02T14:07:03.821385Z"}],"osv":[{"id":"ALPINE-CVE-2021-33913","description":"libspf2 before 1.2.11 has a 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 SPF_record_expand_data in spf_expand.c. The amount of overflowed data depends on the relationship between the length of an entire domain name and the length of its leftmost label. 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.","status":"published","published":"2022-01-19T18:15:07.83Z","modified":"2026-10-23T17:17:56.191304534Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:27:48.646074Z"},{"id":"CVE-2021-33913","description":"libspf2 before 1.2.11 has a 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 SPF_record_expand_data in spf_expand.c. The amount of overflowed data depends on the relationship between the length of an entire domain name and the length of its leftmost label. 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.","status":"published","published":"2022-01-19T18:15:07.83Z","modified":"2026-03-15T22:37:19.120873Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:44:20.13324Z"},{"id":"DEBIAN-CVE-2021-33913","description":"libspf2 before 1.2.11 has a 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 SPF_record_expand_data in spf_expand.c. The amount of overflowed data depends on the relationship between the length of an entire domain name and the length of its leftmost label. 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.","status":"published","published":"2022-01-19T18:15:07.83Z","modified":"2026-10-23T18:03:03.124172912Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:45:35.233346Z"},{"id":"UBUNTU-CVE-2021-33913","description":"libspf2 before 1.2.11 has a 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 SPF_record_expand_data in spf_expand.c. The amount of overflowed data depends on the relationship between the length of an entire domain name and the length of its leftmost label. 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.","status":"published","published":"2022-01-19T18:15:00Z","modified":"2026-04-22T12:55:08.940479Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:54:27.870979Z"},{"id":"DLA-2890-1","title":"libspf2 - security update","status":"published","published":"2022-01-21T00:00:00Z","modified":"2026-03-09T01:21:55.192003Z","updated_at":"2026-11-02T15:46:11.189256Z"},{"id":"USN-6584-1","title":"libspf2 vulnerabilities","description":"Philipp Jeitner and Haya Shulman discovered that Libspf2 incorrectly handled\ncertain inputs. If a user or an automated system were tricked into opening a\nspecially crafted input file, a remote attacker could possibly use this issue\nto cause a denial of service or execute arbitrary code. (CVE-2021-20314)\n\nIt was discovered that Libspf2 incorrectly handled certain inputs. If a user or\nan automated system were tricked into opening a specially crafted input file, a\nremote attacker could possibly use this issue to cause a denial of service or\nexecute arbitrary code. This issue only affected Ubuntu 18.04 LTS and \nUbuntu 20.04 LTS. (CVE-2021-33912, CVE-2021-33913)\n","status":"published","published":"2024-01-15T17:17:57Z","modified":"2026-06-25T13:31:51.737671436Z","updated_at":"2026-11-02T16:58:17.305935Z"},{"id":"USN-6584-2","title":"libspf2 vulnerabilities","description":"USN-6584-1 fixed several vulnerabilities in Ubuntu 18.04 LTS and\nUbuntu 20.04 LTS. This update provides the corresponding updates for\nCVE-2021-33912 and CVE-2021-33913 in Ubuntu 16.04 LTS.\n\nWe apologize for the inconvenience.\n\nOriginal advisory details:\n\n Philipp Jeitner and Haya Shulman discovered that Libspf2 incorrectly handled\n certain inputs. If a user or an automated system were tricked into opening a\n specially crafted input file, a remote attacker could possibly use this issue\n to cause a denial of service or execute arbitrary code. (CVE-2021-20314)\n \n It was discovered that Libspf2 incorrectly handled certain inputs. If a user or\n an automated system were tricked into opening a specially crafted input file, a\n remote attacker could possibly use this issue to cause a denial of service or\n execute arbitrary code. This issue only affected Ubuntu 18.04 LTS and \n Ubuntu 20.04 LTS. (CVE-2021-33912, CVE-2021-33913)\n","status":"published","published":"2024-02-21T10:40:23Z","modified":"2026-06-25T13:30:40.067058078Z","updated_at":"2026-11-02T16:58:17.305935Z"}]}}