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 MAXIMUMICALIMPORTSIZEBYTES and MAXIMUMICALIMPORT_EVENTS limits, uses transaction savepoints, and validates event URLs. This issue is fixed in versions 5.2.4 and 6.0.1.
{
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55247.json",
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-400"
]
}{
"source": [
"AFFECTED_FIELD",
"REFERENCES"
],
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "5.2.4"
},
{
"introduced": "6.0.0"
},
{
"fixed": "6.0.1"
}
]
}