{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "plone.app.event",
          "vendor": "plone",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 5.2.4"
            },
            {
              "status": "affected",
              "version": "\u003e= 6.0.0, \u003c 6.0.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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\u0027s 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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 9.1,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-400",
              "description": "CWE-400: Uncontrolled Resource Consumption",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-28T18:59:01.212Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/plone/plone.app.event/security/advisories/GHSA-r82h-mqw3-fc56",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/plone/plone.app.event/security/advisories/GHSA-r82h-mqw3-fc56"
        },
        {
          "name": "https://github.com/plone/plone.app.event/commit/1e3c83c15a24d1a789cdb012593505bc5620e28e",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/plone/plone.app.event/commit/1e3c83c15a24d1a789cdb012593505bc5620e28e"
        },
        {
          "name": "https://github.com/plone/plone.app.event/commit/4de5eb3ea9e4f7f1781622e6d64fc086629d1437",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/plone/plone.app.event/commit/4de5eb3ea9e4f7f1781622e6d64fc086629d1437"
        },
        {
          "name": "https://github.com/plone/plone.app.event/releases/tag/5.2.4",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/plone/plone.app.event/releases/tag/5.2.4"
        },
        {
          "name": "https://github.com/plone/plone.app.event/releases/tag/6.0.1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/plone/plone.app.event/releases/tag/6.0.1"
        }
      ],
      "source": {
        "advisory": "GHSA-r82h-mqw3-fc56",
        "discovery": "UNKNOWN"
      },
      "title": "plone.app.event: Denial of service via iCalendar import"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-55247",
    "datePublished": "2026-08-28T18:59:01.212Z",
    "dateReserved": "2026-06-16T16:44:00.624Z",
    "dateUpdated": "2026-08-28T18:59:01.212Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}