PYSEC-2026-3883

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Import Source

https://github.com/pypa/advisory-database/blob/main/vulns/plone-app-event/PYSEC-2026-3883.yaml

JSON Data

https://api.osv.dev/v1/vulns/PYSEC-2026-3883

Aliases

Published

2026-09-10T09:44:58Z

Modified

2026-09-10T12:15:10Z

Severity

9.1 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H CVSS Calculator

Summary

plone.app.event vulnerable to denial of service via iCalendar import

Details

Impact

By abusing the iCalendar import functionality, a logged-in editor could take the whole site offline, make the server reach into the internal network and read calendar files off disk (SSRF), and store XSS.

Patches

The problem has been patched in plone.app.event.

For Plone 6.2: upgrade to plone.app.event 6.0.1
For Plone 6.1: upgrade to plone.app.event 5.2.4
For Plone 6.0: upgrade to plone.app.event 5.2.4

Workarounds

In the site root, go to the Security tab of the Zope Management Interface (manage_access), look for the "plone.app.event: Import Ical" permission, and grant this only to the Manager role. Then only users with the Manager role can use the ical import form.

There is no workaround for the stored XSS in the URL field of events.

The vulnerabilities were discovered by Timothy Dudley and responsibly reported to the Plone Security Team. Thank you!

References

Affected packages

PyPI / plone-app-event

Package

Name: plone-app-event; View open source insights on deps.dev
Purl: pkg:pypi/plone-app-event

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0 Unknown introduced version / All previous versions are affected

Fixed

5.2.4

Introduced

6.0.0a1

Fixed

6.0.1

Affected versions

1.*

1.0a1

1.0a2

1.0b1

1.0b2

1.0b3

1.0b4

1.0b5

1.0b6

1.0b7

1.0b8

1.0rc1

1.0rc2

1.0rc3

1.0

1.0.1

1.0.2

1.0.3

1.0.4

1.0.5

1.0.6

1.1.a1

1.1b1

1.1

1.1.1

1.1.2

1.1.3

1.1.4

1.1.5

1.1.6

1.1.7

1.1.8

1.1.10

1.1.11

1.1.12

1.1.13

1.2

1.2.1

1.2.2

1.2.3

1.2.4

1.2.5

1.2.6

1.2.7

2.*

2.0a1

2.0a2

2.0a3

2.0a4

2.0a5

2.0a6

2.0a7

2.0a8

2.0a9

2.0a10

2.0a11

2.0a12

2.0a13

2.0b1

2.0b2

2.0

2.0.1

2.0.2

2.0.3

2.0.4

2.0.5

2.0.6

2.0.7

2.0.8

2.0.9

2.0.10

2.0.11

2.0.12

2.0.13

2.0.14

2.0.15

3.*

3.0

3.0.1

3.0.2

3.0.3

3.0.4

3.0.5

3.0.6

3.0.7

3.1

3.1.1

3.2.0

3.2.1

3.2.2

3.2.3

3.2.4

3.2.5

3.2.6

3.2.7

3.2.8

3.2.9

3.2.10

3.2.11

3.2.12

3.2.13

3.2.14

4.*

4.0.0a1

4.0.0a2

4.0.0a3

4.0.0a4

4.0.0a5

4.0.0a6

4.0.0a7

4.0.0a8

4.0.0a9

4.0.0b1

4.0.0

5.*

5.0.0

5.0.1

5.1.0

5.1.1

5.1.2

5.1.3

5.1.4

5.1.5

5.1.6

5.1.7

5.1.8

5.2.0

5.2.1

5.2.2

5.2.3

6.*

6.0.0a1

6.0.0a2

6.0.0

Database specific

source

"https://github.com/pypa/advisory-database/blob/main/vulns/plone-app-event/PYSEC-2026-3883.yaml"