plone.app.portlets vulnerable to denial of service via RSS feed portletGHSA-x5g3-w747-2h8q
CRITICALFix: plone/plone.app.portlets@09da52eGHSA-x5g3-w747-2h8q is a critical-severity (CVSS 9.1) Uncontrolled Resource Consumption vulnerability in plone-app-portlets. A fix is available for plone-app-portlets — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-x5g3-w747-2h8q.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-x5g3-w747-2h8q by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
plone-app-portlets🐍plone-app-portlets🐍plone-app-portletsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | plone-app-portlets | ≥ 7.0.0&&< 7.0.2 | 7.0.2pip install --upgrade 'plone-app-portlets==7.0.2' |
| 🐍PyPI | plone-app-portlets | ≥ 6.0.0&&< 6.0.4 | 6.0.4pip install --upgrade 'plone-app-portlets==6.0.4' |
| 🐍PyPI | plone-app-portlets | all versions | 5.0.8pip install --upgrade 'plone-app-portlets==5.0.8' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for plone-app-portlets, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update plone-app-portlets to 7.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-x5g3-w747-2h8q is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is GHSA-x5g3-w747-2h8q in your dependencies?
Find it across PyPI, including transitive dependencies.