Invoking bypass of FIDO/U2F security keys physical interaction in golang.org/x/crypto/ssh_CVE-2026-39831

{
    "lastseen": "",
    "description": "The Verify() method for FIDO/U2F security key types ([email protected], [email protected]) did not check the User Presence flag. Signatures generated without physical touch were accepted, allowing unattended use of a hardware security key. To restore the previous behavior, return a \"no-touch-required\" extension in Permissions.Extensions from PublicKeyCallback.",
    "published": "2026-05-22T02:31:27.436Z",
    "modified": "2026-05-22T18:52:08.344Z",
    "type": "cve",
    "title": "Invoking  bypass of FIDO/U2F security keys physical interaction in golang.org/x/crypto/ssh",
    "source": "Go",
    "references": "https://go.dev/issue/79566\nhttps://groups.google.com/g/golang-announce/c/a082jnz-LvI\nhttps://go.dev/cl/781662\nhttps://pkg.go.dev/vuln/GO-2026-5019",
    "id": "CVE-2026-39831",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "golang.org/x/crypto golang.org/x/crypto/ssh 0",
    "sourceHref": "",
    "cvss": {
        "score": 9.1,
        "severity": "CRITICAL",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
        "version": "3.1"
    },
    "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": "golang.org/x/crypto/ssh",
    "version": "0",
    "vendor": "golang.org/x/crypto",
    "ai_description": "Bypass of FIDO/U2F security keys physical interaction in golang.org/x/crypto/ssh due to missing User Presence flag check",
    "ai_severity": "Critical",
    "ai_vendor": "The Go Authors",
    "ai_product": "golang.org/x/crypto/ssh",
    "ai_version": "0",
    "ai_score": 9.1
}