Plone app event up to 5.2.3/6.0.0 Importer importer.py server-side request forgery

Summaryinfo

A vulnerability labeled as critical has been found in Plone app event up to 5.2.3/6.0.0. The impacted element is an unknown function of the file src/plone/app/event/ical/importer.py of the component Importer. Such manipulation leads to server-side request forgery. This vulnerability is traded as CVE-2026-55247. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in Plone app event up to 5.2.3/6.0.0. It has been rated as critical. Affected by this issue is an unknown part of the file src/plone/app/event/ical/importer.py of the component Importer. The manipulation with an unknown input leads to a server-side request forgery vulnerability. Using CWE to declare the problem leads to CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-55247 since 06/16/2026. The exploitation is known to be easy. The attack may be launched remotely. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit.

Upgrading to version 5.2.4 or 6.0.1 eliminates this vulnerability.

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Productinfo

Type

• Content Management System

Vendor

• Plone

Name

• app event

Version

• 5.2.0
• 5.2.1
• 5.2.2
• 5.2.3
• 6.0

License

• open-source

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CPE 2.2info

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