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Advisory record · GHSA-wq6x-g685-w5f2

Improper Restriction of XML External Entity Reference in Plone

CVSS 8.8 HighEPSS 0.015 · 73rd percentile

Published by the GitHub Advisory Database at 7 Apr 2021, 21:13 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
plonePyPI<5.2.35.2.3
plone-app-eventPyPI<3.2.103.2.10
plone-app-themingPyPI<4.1.64.1.6
plone-app-dexterityPyPI<2.6.82.6.8
plone-supermodelPyPI<1.6.31.6.3
Identifiers
GHSA-wq6x-g685-w5f2 · CVE-2020-28734 · PYSEC-2020-246 · PYSEC-2026-2880 · PYSEC-2026-2883 · PYSEC-2026-2886 · PYSEC-2026-736
Weakness (CWE)
CWE-611
Tags
Published
7 Apr 2021
Updated
13 Jul 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Plone before 5.2.3 is vulnerable to XML external entity (XXE) attacks through a feature that is limited to the Manager role, and the affected packages include plone-app-event before 3.2.10, plone-app-theming before 4.1.6, plone-app-dexterity before 2.6.8, and plone-supermodel before 1.6.3. An attacker with Manager-level access could exploit this to read or disclose data through XML external entities. Upgrade plone to 5.2.3 or later and the other listed packages to their fixed versions. The source gives few details about the specific feature.

Written 6 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
8.8 High 3.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H GitHub Advisory Database
  • CISA KEV Not listed.
  • EPSS 0.015, the 73rd percentile, on 12 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 15:01 UTC First seen by agentprime
  2. 31 Oct 2026, 15:01 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.