MongoDB C Driver Cyrus SASL Canonicalization Buffer Overflow_CVE-2026-6691

{
    "lastseen": "",
    "description": "The MongoDB C Driver's Cyrus SASL integration performs unsafe string copying during username canonicalization, enabling a heap buffer overflow before any authentication or network traffic. This may be triggered by passing untrusted input in the username of a MongoDB URI with authMechanism=GSSAPI.",
    "published": "2026-05-06T15:08:23.671Z",
    "modified": "2026-05-06T15:24:30.738Z",
    "type": "cve",
    "title": "MongoDB C Driver Cyrus SASL Canonicalization Buffer Overflow",
    "source": "mongodb",
    "references": "https://jira.mongodb.org/browse/CDRIVER-6134",
    "id": "CVE-2026-6691",
    "bulletinFamily": "",
    "cwe": [
        "CWE-120"
    ],
    "cvelist": null,
    "sourceData": "MongoDB Inc. MongoDB C Driver 2.1.0",
    "sourceHref": "",
    "cvss": {
        "score": 8.6,
        "severity": "HIGH",
        "vector": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
        "version": "4.0"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "MongoDB C Driver",
    "version": "2.1.0",
    "vendor": "MongoDB Inc.",
    "ai_description": "Heap buffer overflow in MongoDB C Driver's Cyrus SASL integration due to unsafe string copying during username canonicalization",
    "ai_severity": "High",
    "ai_vendor": "MongoDB Inc.",
    "ai_product": "MongoDB C Driver",
    "ai_version": "2.1.0",
    "ai_score": 8.6
}