{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "0.8.2"
              }
            ],
            "source": "DESCRIPTION"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "d3243651cb142e3e04f3e4bc037b9e985878f444"
            }
          ],
          "repo": "https://github.com/101arrowz/fflate",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "seal",
    "cwe_ids": [
      "CWE-400",
      "CWE-835"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45820.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "0.5.0"
          },
          {
            "last_affected": "0.5.3"
          },
          {
            "introduced": "0.6.0"
          },
          {
            "last_affected": "0.6.10"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "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.",
  "id": "CVE-2026-45820",
  "modified": "2026-07-25T03:56:32.296652820Z",
  "published": "2026-07-22T06:57:13.726Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/101arrowz/fflate/blob/f7873560ad229c22c4b23b06c6a3806ffde77569/src/index.ts#L2714"
    },
    {
      "type": "WEB",
      "url": "https://www.npmjs.com/package/fflate"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45820.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45820"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "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",
      "type": "CVSS_V4"
    }
  ]
}