{
    "id": "CVE-2021-34813",
    "published": "2021-06-16 18:15:09",
    "last_modified": "2026-06-17 03:56:36",
    "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": "Matrix libolm before 3.2.3 allows a malicious Matrix homeserver to crash a client (while it is attempting to retrieve an Olm encrypted room key backup from the homeserver) because olm_pk_decrypt has a stack-based buffer overflow. Remote code execution might be possible for some nonstandard build configurations.",
    "epss_score": "0.04262",
    "epss_percentile": "0.90813",
    "kev": 0,
    "kev_due": null,
    "has_exploit": 0,
    "updated_at": "2026-10-08 18:17:28",
    "priority": {
        "rank": 3,
        "label": "In your normal cycle",
        "why": "Critical by CVSS (9.8), but no sign of active exploitation."
    },
    "products": [
        {
            "vendor": "matrix",
            "product": "olm"
        }
    ],
    "kev_detail": null,
    "exploits": [],
    "refs_list": [
        "https://gitlab.matrix.org/matrix-org/olm/-/commit/ccc0d122ee1b4d5e5ca4ec1432086be17d5f901b",
        "https://gitlab.matrix.org/matrix-org/olm/-/releases/3.2.3",
        "https://matrix.org/blog/2021/06/14/adventures-in-fuzzing-libolm",
        "https://gitlab.matrix.org/matrix-org/olm/-/commit/ccc0d122ee1b4d5e5ca4ec1432086be17d5f901b",
        "https://gitlab.matrix.org/matrix-org/olm/-/releases/3.2.3",
        "https://matrix.org/blog/2021/06/14/adventures-in-fuzzing-libolm"
    ]
}