{"api_version":"1","generated_at":"2026-07-23T14:33:42+00:00","cve":"CVE-2021-33912","urls":{"html":"https://cve.report/CVE-2021-33912","api":"https://cve.report/api/cve/CVE-2021-33912.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2021-33912","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-33912"},"summary":{"title":"CVE-2021-33912","description":"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.","state":"PUBLIC","assigner":"cve@mitre.org","published_at":"2022-01-19 18:15:00","updated_at":"2024-01-15 17:15:00"},"problem_types":["CWE-787"],"metrics":[],"references":[{"url":"https://nathanielbennett.com/blog/libspf2-cve-jan-2022-disclosure","name":"https://nathanielbennett.com/blog/libspf2-cve-jan-2022-disclosure","refsource":"MISC","tags":[],"title":"CVE-2021-33912 and CVE-2021-33913: Heap overflows in email validation library LibSPF2 | Nathaniel Bennett","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://github.com/shevek/libspf2/tree/8131fe140704eaae695e76b5cd09e39bd1dd220b","name":"https://github.com/shevek/libspf2/tree/8131fe140704eaae695e76b5cd09e39bd1dd220b","refsource":"MISC","tags":[],"title":"GitHub - shevek/libspf2 at 8131fe140704eaae695e76b5cd09e39bd1dd220b","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://security.gentoo.org/glsa/202401-22","name":"GLSA-202401-22","refsource":"","tags":[],"title":"libspf2: Multiple vulnerabilities (GLSA 202401-22) — Gentoo security","mime":"text/html","httpstatus":"200","archivestatus":"200"},{"url":"https://lists.debian.org/debian-lts-announce/2022/01/msg00015.html","name":"[debian-lts-announce] 20220121 [SECURITY] [DLA 2890-1] libspf2 security update","refsource":"MLIST","tags":[],"title":"[SECURITY] [DLA 2890-1] libspf2 security update","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-33912","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-33912","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2021","cve_id":"33912","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"debian","cpe5":"debian_linux","cpe6":"9.0","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2021","cve_id":"33912","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"libspf2_project","cpe5":"libspf2","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[{"cve":"CVE-2021-33912","qid":"179014","title":"Debian Security Update for libspf2 (DLA 2890-1)"},{"cve":"CVE-2021-33912","qid":"179776","title":"Debian Security Update for libspf2 (CVE-2021-33912)"},{"cve":"CVE-2021-33912","qid":"200049","title":"Ubuntu Security Notification for Libspf2 Vulnerabilities (USN-6584-1)"},{"cve":"CVE-2021-33912","qid":"200128","title":"Ubuntu Security Notification for Libspf2 Vulnerabilities (USN-6584-2)"},{"cve":"CVE-2021-33912","qid":"502222","title":"Alpine Linux Security Update for libspf2"},{"cve":"CVE-2021-33912","qid":"503678","title":"Alpine Linux Security Update for libspf2"},{"cve":"CVE-2021-33912","qid":"505886","title":"Alpine Linux Security Update for libspf2"},{"cve":"CVE-2021-33912","qid":"710839","title":"Gentoo Linux libspf2 Multiple Vulnerabilities (GLSA 202401-22)"}]},"source_records":{"cve_program":{"CVE_data_meta":{"ASSIGNER":"cve@mitre.org","ID":"CVE-2021-33912","STATE":"PUBLIC"},"affects":{"vendor":{"vendor_data":[{"product":{"product_data":[{"product_name":"n/a","version":{"version_data":[{"version_value":"n/a"}]}}]},"vendor_name":"n/a"}]}},"data_format":"MITRE","data_type":"CVE","data_version":"4.0","description":{"description_data":[{"lang":"eng","value":"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."}]},"problemtype":{"problemtype_data":[{"description":[{"lang":"eng","value":"n/a"}]}]},"references":{"reference_data":[{"refsource":"MISC","name":"https://github.com/shevek/libspf2/tree/8131fe140704eaae695e76b5cd09e39bd1dd220b","url":"https://github.com/shevek/libspf2/tree/8131fe140704eaae695e76b5cd09e39bd1dd220b"},{"refsource":"MISC","name":"https://nathanielbennett.com/blog/libspf2-cve-jan-2022-disclosure","url":"https://nathanielbennett.com/blog/libspf2-cve-jan-2022-disclosure"},{"refsource":"MLIST","name":"[debian-lts-announce] 20220121 [SECURITY] [DLA 2890-1] libspf2 security update","url":"https://lists.debian.org/debian-lts-announce/2022/01/msg00015.html"}]}},"nvd":{"publishedDate":"2022-01-19 18:15:00","lastModifiedDate":"2024-01-15 17:15:00","problem_types":["CWE-787"],"metrics":{"baseMetricV3":{"cvssV3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH","baseScore":9.8,"baseSeverity":"CRITICAL"},"exploitabilityScore":3.9,"impactScore":5.9},"baseMetricV2":{"cvssV2":{"version":"2.0","vectorString":"AV:N/AC:M/Au:N/C:C/I:C/A:C","accessVector":"NETWORK","accessComplexity":"MEDIUM","authentication":"NONE","confidentialityImpact":"COMPLETE","integrityImpact":"COMPLETE","availabilityImpact":"COMPLETE","baseScore":9.3},"severity":"HIGH","exploitabilityScore":8.6,"impactScore":10,"acInsufInfo":false,"obtainAllPrivilege":false,"obtainUserPrivilege":false,"obtainOtherPrivilege":false,"userInteractionRequired":false}},"configurations":{"CVE_data_version":"4.0","nodes":[{"operator":"OR","children":[],"cpe_match":[{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:libspf2_project:libspf2:*:*:*:*:*:*:*:*","versionEndExcluding":"1.2.11","cpe_name":[]}]},{"operator":"OR","children":[],"cpe_match":[{"vulnerable":true,"cpe23Uri":"cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*","cpe_name":[]}]}]}},"legacy_mitre":{"record":{"CveYear":"2021","CveId":"33912","Ordinal":"209363","Title":"CVE-2021-33912","CVE":"CVE-2021-33912","Year":"2021"},"notes":[{"CveYear":"2021","CveId":"33912","Ordinal":"1","NoteData":"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.","Type":"Description","Title":null},{"CveYear":"2021","CveId":"33912","Ordinal":"2","NoteData":"2022-01-19","Type":"Other","Title":"Published"},{"CveYear":"2021","CveId":"33912","Ordinal":"3","NoteData":"2022-01-20","Type":"Other","Title":"Modified"}]}}}