CVE-2026-55247
plone.app.event vulnerable to denial of service via iCalendar import
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | plone.app.event | < 5.2.4 | 5.2.4 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-r82h-mqw3-fc56
- https://github.com/plone/plone.app.event/security/advisories/GHSA-r82h-mqw3-fc56
- https://github.com/plone/plone.app.event/commit/1e3c83c15a24d1a789cdb012593505bc5620e28e
- https://github.com/plone/plone.app.event/commit/4de5eb3ea9e4f7f1781622e6d64fc086629d1437
- https://github.com/plone/plone.app.event/releases/tag/5.2.4
- https://github.com/plone/plone.app.event/releases/tag/6.0.1