{
    "id": "CVE-2021-33912",
    "published": "2022-01-19 18:15:07",
    "last_modified": "2026-06-17 03:55:22",
    "cvss_score": "9.8",
    "cvss_severity": "CRITICAL",
    "cvss_version": "3.1",
    "cvss_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
    "cwe": "CWE-787",
    "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.",
    "epss_score": "0.09643",
    "epss_percentile": "0.95358",
    "kev": 0,
    "kev_due": null,
    "has_exploit": 0,
    "updated_at": "2026-10-05 18:17:26",
    "priority": {
        "rank": 3,
        "label": "In your normal cycle",
        "why": "Critical by CVSS (9.8), but no sign of active exploitation."
    },
    "products": [
        {
            "vendor": "debian",
            "product": "debian_linux"
        },
        {
            "vendor": "libspf2_project",
            "product": "libspf2"
        }
    ],
    "kev_detail": null,
    "exploits": [],
    "refs_list": [
        "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",
        "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"
    ]
}