FKIE_CVE-2026-55247

Vulnerability from fkie_nvd - Published: 2026-08-28 20:18 - Updated: 2026-09-09 21:09
Severity
9.1 (Critical) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H
Summary
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.
References
security-advisories@github.comhttps://github.com/plone/plone.app.event/commit/1e3c83c15a24d1a789cdb012593505bc5620e28e
security-advisories@github.comhttps://github.com/plone/plone.app.event/commit/4de5eb3ea9e4f7f1781622e6d64fc086629d1437
security-advisories@github.comhttps://github.com/plone/plone.app.event/releases/tag/5.2.4
security-advisories@github.comhttps://github.com/plone/plone.app.event/releases/tag/6.0.1
security-advisories@github.comhttps://github.com/plone/plone.app.event/security/advisories/GHSA-r82h-mqw3-fc56
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "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"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "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."
    }
  ],
  "id": "CVE-2026-55247",
  "lastModified": "2026-09-09T21:09:13.080",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "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"
        },
        "exploitabilityScore": 3.1,
        "impactScore": 5.3,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-55247",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-08-31T18:48:16.302616Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-28T20:18:26.890",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/plone/plone.app.event/commit/1e3c83c15a24d1a789cdb012593505bc5620e28e"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/plone/plone.app.event/commit/4de5eb3ea9e4f7f1781622e6d64fc086629d1437"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/plone/plone.app.event/releases/tag/5.2.4"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/plone/plone.app.event/releases/tag/6.0.1"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/plone/plone.app.event/security/advisories/GHSA-r82h-mqw3-fc56"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-400"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.