How severe is CVE-2021-33926?

CVE-2021-33926 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-33926 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-33926?

CVE-2021-33926 primarily affects Plone. In total, 52 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-33926?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-33926 published?

CVE-2021-33926 was published on 2023-02-17 and last updated on 2026-06-17.

CVE-2021-33926

CVE-2021-33926 is a high-severity vulnerability in Plone with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-918.

Key facts

Severity: High (CVSS 3.x base score 8.8)
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-918
Affected product: Plone
Published: 2023-02-17
Last modified: 2026-06-17

Description

An issue in Plone CMS v. 5.2.4, 5.2.3, 5.2.2, 5.2.1, 5.2.0, 5.1rc2, 5.1rc1, 5.1b4, 5.1b3, 5.1b2, 5.1a2, 5.1a1, 5.1.7, 5.1.6, 5.1.5, 5.1.4, 5.1.2, 5.1.1 5.1, 5.0rc3, 5.0rc2, 5.0rc1, 5.0.9, 5.0.8, 5.0.7, 5.0.6, 5.0.5, 5.0.4, 5.0.3, 5.0.2, 5.0.10, 5.0.1, 5.0, 4.3.9, 4.3.8, 4.3.7, 4.3.6, 4.3.5, 4.3.4, 4.3.3, 4.3.20, 4 allows attacker to access sensitive information via the RSS feed protlet.

Frequently asked questions

What is CVE-2021-33926?: An issue in Plone CMS v. 5.2.4, 5.2.3, 5.2.2, 5.2.1, 5.2.0, 5.1rc2, 5.1rc1, 5.1b4, 5.1b3, 5.1b2, 5.1a2, 5.1a1, 5.1.7, 5.1.6, 5.1.5, 5.1.4, 5.1.2, 5.1.1 5.1, 5.0rc3, 5.0rc2, 5.0rc1, 5.0.9, 5.0.8, 5.0.7, 5.0.6, 5.0.5, 5.0.4, 5.0.3, 5.0.2, 5.0.10, 5.0.1, 5.0, 4.3.9, 4.3.8, 4.3.7, 4.3.6, 4.3.5, 4.3.4, 4.3.3, 4.3.20, 4 allows attacker to access sensitive information via the RSS feed protlet.
How severe is CVE-2021-33926?: CVE-2021-33926 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-33926 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-33926?: CVE-2021-33926 primarily affects Plone. In total, 52 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-33926?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-33926 published?: CVE-2021-33926 was published on 2023-02-17 and last updated on 2026-06-17.

References

Affected products (52)

cpe:2.3:a:plone:plone:4.3:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.1:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.2:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.3:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.4:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.5:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.6:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.7:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.8:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.9:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.10:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.11:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.12:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.14:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.15:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.17:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.18:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.19:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:4.3.20:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.0:-:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.0:rc1:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.0:rc2:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.0:rc3:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.0.1:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.0.2:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.0.3:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.0.4:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.0.5:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.0.6:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.0.7:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.0.8:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.0.9:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.0.10:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.1:alpha2:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.1.1:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.1.2:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.1.4:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.1.5:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.1.6:*:*:*:*:*:*:*
cpe:2.3:a:plone:plone:5.1.7:*:*:*:*:*:*:*

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