{
  "cveId": "CVE-2026-53539",
  "url": "https://patchblox.com/security/cve/CVE-2026-53539",
  "summary": "CVE-2026-53539 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-53539, released June 22, 2026. It is not reported as exploited. Patch Radar priority: High.",
  "title": "python-multipart: Python-Multipart is a streaming multipart parser for Python",
  "description": "Python-Multipart is a streaming multipart parser for Python. Prior to 0.0.30, when parsing application/x-www-form-urlencoded bodies, QuerystringParser located the field separator with a two step lookup: it first scanned the entire remaining buffer for \u0026, and only when no \u0026 existed anywhere ahead did it fall back to scanning for ;. For a body that uses ; as the separator and contains no \u0026, every field iteration performed a full failed \u0026 scan over the entire remaining buffer before locating the nearby ;. With N semicolon separated fields in a chunk of size B, this yields O(B^2) byte comparisons per chunk. An attacker can submit a small crafted body of the form a;a;a;... and cause the parser to spend seconds of CPU per request. A handful of concurrent requests can exhaust worker processes. This vulnerability is fixed in 0.0.30.",
  "published": "2026-06-22T18:16:44Z",
  "severity": "high",
  "cvss": 7.5,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
  "epss": 0.0046,
  "epssPercentile": 0.40092,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "python-multipart",
      "release": "Debian 14",
      "fixedVersion": "0.0.32-1",
      "fix": "DEBIAN-CVE-2026-53539",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-53539",
      "released": "2026-06-22T18:16:44Z"
    },
    {
      "platform": "linux",
      "product": "python-python-multipart",
      "release": "opensuse-leap 16.0",
      "fixedVersion": "0.0.20-160000.5.1",
      "fix": "OPENSUSE-SU-2026:21066-1",
      "url": "https://patchblox.com/security/fix/linux/opensuse-su-2026-21066-1",
      "released": "2026-06-26T07:58:44Z"
    },
    {
      "platform": "linux",
      "product": "python-python-multipart",
      "release": "sles 16.0",
      "fixedVersion": "0.0.20-160000.5.1",
      "fix": "SUSE-SU-2026:22372-1",
      "url": "https://patchblox.com/security/fix/linux/suse-su-2026-22372-1",
      "released": "2026-06-26T07:58:40Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T13:06:02Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}