CVE-2026-55247
plone.app.event: Denial of service via iCalendar import
- Published
- Updated
- Reserved
- Assigned by
- GitHub_M
Description
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Critical9.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H |
| NVDNVD · Deferred | 3.1 | Critical9.1 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H |
- EPSS (exploitation in 30 days)
- 0.44% · top 62% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.1.
Weakness
Affected products
- affected < 5.2.4
- affected >= 6.0.0, < 6.0.1
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIplone.app.eventGHSA-r82h-mqw3-fc56 (opens in a new tab)
References (5)
- https://github.com/plone/plone.app.event/security/advisories/GHSA-r82h-mqw3-fc56 (opens in a new tab)x_refsource_CONFIRM
- https://github.com/plone/plone.app.event/commit/1e3c83c15a24d1a789cdb012593505bc5620e28e (opens in a new tab)x_refsource_MISC
- https://github.com/plone/plone.app.event/commit/4de5eb3ea9e4f7f1781622e6d64fc086629d1437 (opens in a new tab)x_refsource_MISC
- https://github.com/plone/plone.app.event/releases/tag/5.2.4 (opens in a new tab)x_refsource_MISC
- https://github.com/plone/plone.app.event/releases/tag/6.0.1 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-r82h-mqw3-fc56 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-55247)Record last updated .