{
    "id": "CVE-2021-3657",
    "published": "2022-02-18 18:15:09",
    "last_modified": "2026-06-17 04:05:31",
    "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-119",
    "description": "A flaw was found in mbsync versions prior to 1.4.4. Due to inadequate handling of extremely large (>=2GiB) IMAP literals, malicious or compromised IMAP servers, and hypothetically even external email senders, could cause several different buffer overflows, which could conceivably be exploited for remote code execution.",
    "epss_score": "0.03488",
    "epss_percentile": "0.88822",
    "kev": 0,
    "kev_due": null,
    "has_exploit": 0,
    "updated_at": "2026-10-09 18:17:29",
    "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": "fedoraproject",
            "product": "fedora"
        },
        {
            "vendor": "isync_project",
            "product": "isync"
        },
        {
            "vendor": "redhat",
            "product": "enterprise_linux"
        }
    ],
    "kev_detail": null,
    "exploits": [],
    "refs_list": [
        "https://bugzilla.redhat.com/show_bug.cgi?id=2028932",
        "https://lists.debian.org/debian-lts-announce/2022/07/msg00001.html",
        "https://security.gentoo.org/glsa/202208-15",
        "https://www.openwall.com/lists/oss-security/2021/12/03/1",
        "https://bugzilla.redhat.com/show_bug.cgi?id=2028932",
        "https://lists.debian.org/debian-lts-announce/2022/07/msg00001.html",
        "https://security.gentoo.org/glsa/202208-15",
        "https://www.openwall.com/lists/oss-security/2021/12/03/1"
    ]
}