{
"id": "GHSA-px8p-9vwx-vf98",
"aliases": [
"CVE-2026-45820"
],
"details": "fflate through 0.8.2 is vulnerable to denial of service via an infinite loop in unzipSync(). A crafted ZIP archive with a central directory entry declaring compressed_size=0xFFFFFFFF (ZIP64 sentinel) but missing the required ZIP64 extra field tag 0x0001 causes z64e() to loop indefinitely due to out-of-bounds reads returning undefined, which coerces to 0, keeping the loop condition permanently true.",
"summary": "fflate unzipSync can enter an infinite loop when parsing malformed ZIP64 archives",
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0.4.5"
},
{
"fixed": "0.4.9"
}
]
}
],
"package": {
"name": "fflate",
"ecosystem": "npm"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0.5.0"
},
{
"fixed": "0.5.4"
}
]
}
],
"package": {
"name": "fflate",
"ecosystem": "npm"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0.6.0"
},
{
"fixed": "0.6.11"
}
]
}
],
"package": {
"name": "fflate",
"ecosystem": "npm"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0.7.0"
},
{
"fixed": "0.7.5"
}
]
}
],
"package": {
"name": "fflate",
"ecosystem": "npm"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0.8.0"
},
{
"fixed": "0.8.3"
}
]
}
],
"package": {
"name": "fflate",
"ecosystem": "npm"
}
}
],
"modified": "2026-09-03T14:58:12Z",
"severity": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
},
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/S:N/AU:Y/R:U/V:D/RE:M/U:Amber"
}
],
"published": "2026-07-22T09:32:13Z",
"references": [
{
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45820",
"type": "ADVISORY"
},
{
"url": "https://github.com/101arrowz/fflate/commit/e6d5e6e1076892f72770ac732d83c81da9f3316e",
"type": "WEB"
},
{
"url": "https://github.com/101arrowz/fflate",
"type": "PACKAGE"
},
{
"url": "https://github.com/101arrowz/fflate/blob/f7873560ad229c22c4b23b06c6a3806ffde77569/src/index.ts#L2714",
"type": "WEB"
},
{
"url": "https://github.com/101arrowz/fflate/releases/tag/v0.8.3",
"type": "WEB"
}
],
"schema_version": "1.4.0",
"database_specific": {
"cwe_ids": [
"CWE-400"
],
"severity": "MODERATE",
"github_reviewed": true,
"nvd_published_at": "2026-07-22T08:16:23Z",
"github_reviewed_at": "2026-09-03T14:58:12Z"
}
}