{"cve":"CVE-2021-33912","nvd":{"published":"2022-01-19T18:15:07.783","modified":"2026-06-17T03:55:22.187","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-787"],"references":["https://github.com/shevek/libspf2/tree/8131fe140704eaae695e76b5cd09e39bd1dd220b","https://lists.debian.org/debian-lts-announce/2022/01/msg00015.html","https://nathanielbennett.com/blog/libspf2-cve-jan-2022-disclosure","https://security.gentoo.org/glsa/202401-22","https://github.com/shevek/libspf2/tree/8131fe140704eaae695e76b5cd09e39bd1dd220b"],"products":["debian:debian_linux","libspf2_project:libspf2"],"source":"nvd","synced_at":"2026-10-19T21:27:20.926095847+00:00"},"epss":{"cve":"CVE-2021-33912","score":0.09643,"percentile":0.95489,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}