phpseclib has a variable-time HMAC comparison in SSH2::get_binary_packet() using != instead of hash_equals()_CVE-2026-40194

{
    "lastseen": "",
    "description": "phpseclib is a PHP secure communications library. Prior to 3.0.51, 2.0.53, and 1.0.28, phpseclib\\Net\\SSH2::get_binary_packet() uses PHP's != operator to compare a received SSH packet HMAC against the locally computed HMAC. != on equal-length binary strings in PHP uses memcmp(), which short-circuits on the first differing byte. This is a real variable-time comparison (CWE-208), proven by scaling benchmarks. This vulnerability is fixed in 3.0.51, 2.0.53, and 1.0.28.",
    "published": "2026-04-10T20:24:06.696Z",
    "modified": "2026-04-10T20:24:06.696Z",
    "type": "cve",
    "title": "phpseclib has a variable-time HMAC comparison in SSH2::get_binary_packet() using != instead of hash_equals()",
    "source": "GitHub_M",
    "references": "https://github.com/phpseclib/phpseclib/security/advisories/GHSA-r854-jrxh-36qx\nhttps://github.com/phpseclib/phpseclib/commit/ffe48b6b1b1af6963327f0a5330e3aa004a194ac\nhttps://github.com/phpseclib/phpseclib/releases/tag/1.0.28\nhttps://github.com/phpseclib/phpseclib/releases/tag/2.0.53\nhttps://github.com/phpseclib/phpseclib/releases/tag/3.0.51",
    "id": "CVE-2026-40194",
    "bulletinFamily": "",
    "cwe": [
        "CWE-208"
    ],
    "cvelist": null,
    "sourceData": "phpseclib phpseclib < 1.0.28\nphpseclib phpseclib >= 2.0.0, < 2.0.53\nphpseclib phpseclib >= 3.0.0, < 3.0.51",
    "sourceHref": "",
    "cvss": {
        "score": 3.7,
        "severity": "LOW",
        "vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/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": "",
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            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "phpseclib",
    "version": "< 1.0.28",
    "vendor": "phpseclib",
    "ai_description": "",
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    "ai_score": 0
}