{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "5.2.4"
              },
              {
                "introduced": "6.0.0"
              },
              {
                "fixed": "6.0.1"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "introduced": "f77cb42d990b2dcdf0d0c5e9baceb9977713565a"
            },
            {
              "fixed": "67343d3385073c618d37f3835e7575e010fa1ca7"
            },
            {
              "fixed": "0bbaa2f5d32625d5cb895089c7d974c775b36ce6"
            },
            {
              "fixed": "1e3c83c15a24d1a789cdb012593505bc5620e28e"
            },
            {
              "fixed": "4de5eb3ea9e4f7f1781622e6d64fc086629d1437"
            }
          ],
          "repo": "https://github.com/plone/plone.app.event",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-r82h-mqw3-fc56"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-400"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55247.json"
  },
  "details": "plone.app.event provides the event content type for Plone. Prior to versions 5.2.4 and 6.0.1, the iCalendar import in src/plone/app/event/ical/importer.py accepts insufficiently restricted calendar and event URLs, does not adequately bound downloaded bytes or imported events, and commits work per event. A logged-in editor can make the server request internal network resources or local calendar files, exhaust resources and take the site offline, and store a malicious event URL that executes script in another user's browser. The fix restricts accepted URLs, applies MAXIMUM_ICAL_IMPORT_SIZE_BYTES and MAXIMUM_ICAL_IMPORT_EVENTS limits, uses transaction savepoints, and validates event URLs. This issue is fixed in versions 5.2.4 and 6.0.1.",
  "id": "CVE-2026-55247",
  "modified": "2026-09-02T03:30:29.532033843Z",
  "published": "2026-08-28T18:59:01.212Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/plone/plone.app.event/releases/tag/5.2.4"
    },
    {
      "type": "WEB",
      "url": "https://github.com/plone/plone.app.event/releases/tag/6.0.1"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55247.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/plone/plone.app.event/security/advisories/GHSA-r82h-mqw3-fc56"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-55247"
    },
    {
      "type": "FIX",
      "url": "https://github.com/plone/plone.app.event/commit/1e3c83c15a24d1a789cdb012593505bc5620e28e"
    },
    {
      "type": "FIX",
      "url": "https://github.com/plone/plone.app.event/commit/4de5eb3ea9e4f7f1781622e6d64fc086629d1437"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "plone.app.event: Denial of service via iCalendar import"
}