Deno: WebSocket API sandbox bypass via missing post-DNS check_CVE-2026-49860

{
    "lastseen": "",
    "description": "Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.8.1, when a WebSocket connection was opened, Deno checked the destination hostname against --deny-net rules but did not re-check the IP addresses that hostname resolved to. An attacker-controlled script could use a specially crafted domain name that passes the hostname check yet resolves to a denied IP, bypassing the network restriction entirely. This vulnerability is fixed in 2.8.1.",
    "published": "2026-06-23T17:15:05.749Z",
    "modified": "2026-06-23T17:37:07.624Z",
    "type": "cve",
    "title": "Deno: WebSocket API sandbox bypass via missing post-DNS check",
    "source": "GitHub_M",
    "references": "https://github.com/denoland/deno/security/advisories/GHSA-83pc-3rw9-qpwj",
    "id": "CVE-2026-49860",
    "bulletinFamily": "",
    "cwe": [
        "CWE-918"
    ],
    "cvelist": null,
    "sourceData": "denoland deno < 2.8.1",
    "sourceHref": "",
    "cvss": {
        "score": 5.2,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
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            "baseScore": 0,
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        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "deno",
    "version": "< 2.8.1",
    "vendor": "denoland",
    "ai_description": "",
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    "ai_score": 0
}