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CVE-2020-28736

Improper Restriction of XML External Entity Reference in Plone

8.8 HighFix available

Plone before 5.2.3 allows XXE attacks via a feature that is protected by an unapplied permission of plone.schemaeditor.ManageSchemata (therefore, only available to the Manager role).

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

1.45%Up 0.6 points since Apr 14, 2021
90%50%10%1%

What each source reports

NVD Score used 8.8

Plone before 5.2.3 allows XXE attacks via a feature that is protected by an unapplied permission of plone.schemaeditor.ManageSchemata (therefore, only available to the Manager role).

Record
CVE-2020-28736
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0
6.5 MediumAV:N/AC:L/Au:S/C:P/I:P/A:P
Weakness
CWE-611
Updated
2026-11-02
CVE List No score

Plone before 5.2.3 allows XXE attacks via a feature that is protected by an unapplied permission of plone.schemaeditor.ManageSchemata (therefore, only available to the Manager role).

Record
CVE-2020-28736
Updated
2026-11-02
EUVDEUVD-2020-0142 No score

Plone before 5.2.3 allows XXE attacks via a feature that is protected by an unapplied permission of plone.schemaeditor.ManageSchemata (therefore, only available to the Manager role).

Record
EUVD-2020-0142
Updated
2026-11-03
GitHub AdvisoriesGHSA-2c8c-84w2-j38j 8.7

Improper Restriction of XML External Entity Reference in Plone

Plone before 5.2.3 allows XXE attacks via a feature that is protected by an unapplied permission of plone.schemaeditor.ManageSchemata (therefore, only available to the Manager role).

Record
GHSA-2c8c-84w2-j38j
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-611
Updated
2026-11-02
OSV 8.8

Plone before 5.2.3 allows XXE attacks via a feature that is protected by an unapplied permission of plone.schemaeditor.ManageSchemata (therefore, only available to the Manager role).

Record
CVE-2020-28736
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVGHSA-2c8c-84w2-j38j 8.7

Improper Restriction of XML External Entity Reference in Plone

Plone before 5.2.3 allows XXE attacks via a feature that is protected by an unapplied permission of plone.schemaeditor.ManageSchemata (therefore, only available to the Manager role).

Record
GHSA-2c8c-84w2-j38j
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-611
Updated
2026-11-02
Show 5 moreShow less
OSVPYSEC-2026-2879 8.7

Improper Restriction of XML External Entity Reference in Plone

Plone before 5.2.3 allows XXE attacks via a feature that is protected by an unapplied permission of plone.schemaeditor.ManageSchemata (therefore, only available to the Manager role).

Record
PYSEC-2026-2879
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVPYSEC-2026-2882 8.7

Improper Restriction of XML External Entity Reference in Plone

Plone before 5.2.3 allows XXE attacks via a feature that is protected by an unapplied permission of plone.schemaeditor.ManageSchemata (therefore, only available to the Manager role).

Record
PYSEC-2026-2882
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVPYSEC-2026-2885 8.7

Improper Restriction of XML External Entity Reference in Plone

Plone before 5.2.3 allows XXE attacks via a feature that is protected by an unapplied permission of plone.schemaeditor.ManageSchemata (therefore, only available to the Manager role).

Record
PYSEC-2026-2885
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVPYSEC-2026-735 8.7

Improper Restriction of XML External Entity Reference in Plone

Plone before 5.2.3 allows XXE attacks via a feature that is protected by an unapplied permission of plone.schemaeditor.ManageSchemata (therefore, only available to the Manager role).

Record
PYSEC-2026-735
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVPYSEC-2020-248 No score

Plone before 5.2.3 allows XXE attacks via a feature that is protected by an unapplied permission of plone.schemaeditor.ManageSchemata (therefore, only available to the Manager role).

Record
PYSEC-2020-248
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
plone
PyPI
 before 5.2.3
5.2.3
plone-app-event
PyPI
 before 3.2.10
3.2.10
plone-app-theming
PyPI
 before 4.1.6
4.1.6
plone-app-dexterity
PyPI
 before 2.6.8
2.6.8
plone-supermodel
PyPI
 before 1.6.3
1.6.3
plone
PyPI
 before 5.2.3, plus listed versions
3.23.2.13.2.23.2.33.2a1
Show 45 moreShow less
3.2rc13.33.3.13.3.23.3.33.3.43.3.53.3.63.3b13.3rc13.3rc23.3rc33.3rc43.3rc54.04.0.14.0.104.0.24.0.34.0.44.0.54.0.64.0.74.0.84.0.94.0a14.0a24.0a34.0a44.0a54.0b14.0b24.0b34.0b44.0b54.0rc14.14.1.14.1.24.1.34.1.44.1.54.1.64.1a14.1a2
5.2.3
plone-app-event
PyPI
 before 3.2.10, plus listed versions
1.01.0.11.0.21.0.31.0.4
Show 45 moreShow less
1.0.51.0.61.0a11.0a21.0b11.0b21.0b31.0b41.0b51.0b61.0b71.0b81.0rc11.0rc21.0rc31.11.1.11.1.101.1.111.1.121.1.131.1.21.1.31.1.41.1.51.1.61.1.71.1.81.1.a11.1b11.21.2.11.2.21.2.31.2.41.2.51.2.61.2.72.02.0.12.0.102.0.112.0.122.0.132.0.14
3.2.10
plone-app-theming
PyPI
 before 4.1.6, plus listed versions
1.01.0.11.0.21.0.31.0.4
Show 45 moreShow less
1.0b11.0b21.0b31.0b41.0b51.0b61.0b71.0b81.0b91.11.1.11.1.21.1.31.1.41.1.51.1.61.1.71.1.81.1a11.1a21.1b11.1b21.2.01.2.11.2.101.2.111.2.121.2.131.2.141.2.151.2.161.2.171.2.181.2.191.2.21.2.31.2.41.2.51.2.61.2.71.2.81.2.91.3.01.3.11.3.2
4.1.6
plone-app-dexterity
PyPI
 before 2.6.8, plus listed versions
1.01.0.11.0.21.0.31.0a1
Show 45 moreShow less
1.0a21.0a31.0a41.0a51.0a61.0a71.0b11.0b21.0b31.0b41.0rc11.11.21.2.11.2.22.02.0.12.0.102.0.112.0.122.0.132.0.142.0.152.0.162.0.172.0.182.0.192.0.22.0.32.0.42.0.52.0.62.0.72.0.82.0.92.1.02.1.12.1.102.1.112.1.122.1.132.1.142.1.152.1.162.1.17
2.6.8
plone-supermodel
PyPI
 before 1.6.3, plus listed versions
1.01.0.11.0.21.0.31.0.4
Show 32 moreShow less
1.0b11.0b21.0b31.0b41.0b51.0b61.0b71.0b81.11.1.11.1.21.1.31.1.41.2.01.2.11.2.21.2.31.2.41.2.51.2.61.2.71.3.01.3.11.3.21.3.31.3.41.4.01.4.11.5.01.6.01.6.11.6.2
1.6.3

History

History
RecordedChangedSources
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2020-28736 is a high vulnerability (CVSS 8.8) in Plone, published December 30, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.45%, the 73rd percentile. Fixed in plone 5.2.3.

References

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Left out here: 207 versions. The JSON record has them.

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