plone.app.portlets vulnerable to denial of service via RSS feed portlet
Impact
By adding an RSS portlet, and giving this a link to a very large file, a member can cause a denial of service attack, because Plone will use lots of memory. The member could also use different urls to try to get information about the internal network and open port numbers (SSRF). A malicious RSS feed could cause stored XSS, when the url of a feed item is a javascript url.
Patches
The problem has been patched in plone.app.portlets.
- For Plone 6.2: upgrade to
plone.app.portlets7.0.2 - For Plone 6.1: upgrade to
plone.app.portlets6.0.4 - For Plone 6.0: upgrade to
plone.app.portlets5.0.8
Workarounds
If upgrading is not immediately possible:
- Restrict who can manage portlets: remove the
plone.app.portlets.ManageOwnPortletspermission from untrusted roles, and limit Manage portlets to trusted administrators (usually this is already restricted to the Manager and Site Administrator roles). - Where the RSS portlet is not needed, unregister it so it cannot be added. This would need to be done by editing a
portlets.xmlin your own code, so it is not a quick fix.
References
This is similar to this plone.app.event vulnerability. It was discovered by the Plone Security Team by thinking of similar cases to the plone.app.event problem.
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | plone-app-portlets | >= 7.0.0, < 7.0.2, >= 6.0.0, < 6.0.4, < 5.0.8 | 7.0.2, 6.0.4, 5.0.8 |
References
- https://github.com/plone/plone.app.portlets/security/advisories/GHSA-x5g3-w747-2h8q
- https://github.com/plone/plone.app.portlets/commit/09da52ef7b297daa8e0cfd2361e47c37d9b073ad
- https://github.com/plone/plone.app.portlets/commit/9f16b6fb10211916686c6c346ea174bf517e3fbd
- https://github.com/plone/plone.app.portlets/commit/a3b2c2887165b308cd915cbb87b8276f90a76680
- https://github.com/plone/plone.app.portlets/commit/df5e256baee55083cbd6b9a2623675d4cb26b6cd
- https://github.com/plone/plone.app.portlets
- https://pypi.org/project/plone-app-portlets
- https://github.com/advisories/GHSA-x5g3-w747-2h8q
- https://nvd.nist.gov/vuln/detail/CVE-2026-55248
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H- Weakness (CWE)
CWE-400- Platform
- Python (PyPI)
- Package
plone-app-portlets- Disclosed
- 28.08.2026
- Updated
- 11.10.2026 15:18
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-3884 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-x5g3-w747-2h8q - CC BY 4.0
Vulnerability history: plone-app-portlets
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 2
- First → latest
- 08.2026 09.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 2
Disclosures per year
- 2026: 2
-
plone.app.portlets vulnerable to denial of service via RSS feed portlet this entry
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