---
title: "CVE-2026-55248: plone.app.portlets vulnerable to denial of service via RSS feed portlet"
url: https://erroneo.us/security/cve/CVE-2026-55248/
description: "CVE-2026-55248 (plone.app.portlets (PyPI)): plone.app.portlets provides portlets and a Plone-specific user interface for plone.portlets. Prior to 5.0.8…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-08-28
date_modified: 2026-08-28
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-55248"
kev: false
cvss: 9.1
epss: 0.00441
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-55248: plone.app.portlets vulnerable to denial of service via RSS feed portlet

**Signal:** Critical, preconditions apply. Severe if exploited, but exploitation needs conditions that may not apply to you. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.4% , percentile 37: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 37% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes plone.app.portlets (PyPI) >= 7.0.0, <= 7.0.1, fixed in 7.0.2 ; plone.app.portlets (PyPI) >= 6.0.0, < 6.0.4, fixed in 6.0.4 ; plone.app.portlets (PyPI) < 5.0.8, fixed in 5.0.8 . Check your lockfile, including transitive dependencies.

## What it is

plone.app.portlets provides portlets and a Plone-specific user interface for plone.portlets. Prior to 5.0.8, 6.0.4, and 7.0.2, a member who can add an RSS portlet can set its feed URL to a very large response, causing src/plone/app/portlets/portlets/rss.py to download and retain excessive data in memory and deny service. The same RSS URL handling accepts internal hosts, IP addresses, single-word domains, and explicit ports, allowing server-side requests that can probe internal network services and open ports. A malicious feed item can also supply a JavaScript URL that is retained as the item link and can execute script when used by a victim. The affected logic includes rssfeedurlvalidator, normalurlvalidator, RSSFeed.retrieveFeed, RSSFeed.buildItemDict, and the FEEDDATA in-memory cache. This issue is fixed in versions 5.0.8, 6.0.4, and 7.0.2.

## Affected packages

- PyPI `plone.app.portlets` >= 7.0.0, <= 7.0.1 → fixed: 7.0.2
- PyPI `plone.app.portlets` >= 6.0.0, < 6.0.4 → fixed: 6.0.4
- PyPI `plone.app.portlets` < 5.0.8 → fixed: 5.0.8

## Affected products (CVE record)

- plone plone.app.portlets: < 5.0.8, >= 6.0.0, < 6.0.4, >= 7.0.0, < 7.0.2

## Severity

- GitHub_M CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H`
- GitHub CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable no , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.44% probability of exploitation activity in the next 30 days; percentile 37.

## Sources

- [GitHub Advisory GHSA-x5g3-w747-2h8q](https://github.com/advisories/GHSA-x5g3-w747-2h8q)
- [CVE.org record CVE-2026-55248](https://www.cve.org/CVERecord?id=CVE-2026-55248)
- [NVD entry CVE-2026-55248](https://nvd.nist.gov/vuln/detail/CVE-2026-55248)
- [github.com](https://github.com/plone/plone.app.portlets/security/advisories/GHSA-x5g3-w747-2h8q)
- [github.com](https://github.com/plone/plone.app.portlets/commit/09da52ef7b297daa8e0cfd2361e47c37d9b073ad)
- [github.com](https://github.com/plone/plone.app.portlets/commit/9f16b6fb10211916686c6c346ea174bf517e3fbd)
- [github.com](https://github.com/plone/plone.app.portlets/commit/a3b2c2887165b308cd915cbb87b8276f90a76680)
- [github.com](https://github.com/plone/plone.app.portlets/commit/df5e256baee55083cbd6b9a2623675d4cb26b6cd)

---
Source page: https://erroneo.us/security/cve/CVE-2026-55248/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt