esm.sh: Legacy Route Path Traversal Can Lead to RCE_CVE-2026-44593

{
    "lastseen": "",
    "description": "esm.sh is a no-build content delivery network (CDN) for web development. In 137 and earlier, the legacy router first retrieves a response from legacyServer, parses the incoming request path, and ultimately writes the data to storage via buildStorage.Put. The router concatenates the path components without sanitizing them, producing a storage key. When this key is used, the underlying file system resolves the relative segments and writes the file to the specified path. Thus an attacker can craft a request that writes data to arbitrary locations on the server.",
    "published": "2026-05-28T14:44:20.782Z",
    "modified": "2026-05-28T14:44:20.782Z",
    "type": "cve",
    "title": "esm.sh: Legacy Route Path Traversal Can Lead to RCE",
    "source": "GitHub_M",
    "references": "https://github.com/esm-dev/esm.sh/security/advisories/GHSA-3636-h3vx-6465",
    "id": "CVE-2026-44593",
    "bulletinFamily": "",
    "cwe": [
        "CWE-22"
    ],
    "cvelist": null,
    "sourceData": "esm-dev esm.sh <= 137",
    "sourceHref": "",
    "cvss": {
        "score": 8.7,
        "severity": "HIGH",
        "vector": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/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": "esm.sh",
    "version": "<= 137",
    "vendor": "esm-dev",
    "ai_description": "Legacy Route Path Traversal vulnerability allowing attackers to write data to arbitrary server locations",
    "ai_severity": "High",
    "ai_vendor": "esm-dev",
    "ai_product": "esm.sh",
    "ai_version": "<= 137",
    "ai_score": 8.7
}