Vulnerability in plone.app.portlets (CVE-2026-55248)
Summary
Vulnerability in plone.app.portlets (CVE-2026-55248). Risk of unauthorized operations or information disclosure. Exploitable via plone.app.portlets. Mitigation: upgrade to 5.0.8 or later.
Original description
The description as published by the source.
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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-55248 has been found in plone.app.portlets.
Attackers can target a specific entry point like plone.app.portlets over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 9.1/10.
What to do: upgrade plone.app.portlets to 5.0.8 or later.
If unsure, ask your IT team or search "plone.app.portlets CVE-2026-55248" on the vendor's site.
CVE-2026-55248 (plone.app.portlets) — CWE-400 / CVSS v3 9.1
Attack vector: remote (network-reachable) / no user interaction
Attack surface: plone.app.portlets / plone.app.portlets.ManageOwnPortlets / portlets.xml / plone.app.event
Patched: 5.0.8 — apply immediately
Workaround: - Restrict who can manage portlets: remove the `plone.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-400) exists in plone.app.portlets. Attackers reach the vulnerable code path via plone.app.portlets.
Check the vendor advisory for the affected versions of plone.app.portlets. Attack surface: plone.app.portlets / plone.app.portlets.ManageOwnPortlets / portlets.xml / plone.app.event.
Severity: Critical (CVSS 9.1/10). Risk of unauthorized operations or information disclosure.
Update to 5.0.8.
Workaround: - Restrict who can manage portlets: remove the `plone.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'plone.app.portlets' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'plone.app.portlets' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
plone.app.portletsを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
- Restrict who can manage portlets: remove the `plone.パッチが適用されるまでの応急処置として、- Restrict who can manage portlets: remove the `plone. を実施。回避策の副作用 (機能低下) を確認した上で。
-
3Apply patch patch
Upgrade plone.app.portlets to 5.0.8ステージング環境で 5.0.8 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
4Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。