Cyber Resilience

CVE-2021-33926

HighPublic PoC

Published: 17 February 2023

Published
17 February 2023
Modified
19 March 2025
KEV Added
Patch
CVSS Score v3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0050 66.5th percentile
Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-33926 is a high-severity SSRF (CWE-918) vulnerability in Plone Plone. Its CVSS base score is 8.8 (High).

Operationally, ranked in the top 33.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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,…

more

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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

plone
plone
4.3, 4.3.1, 4.3.10, 4.3.11, 4.3.12

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-918

Penetration testing attempts server-side requests to internal resources, identifying SSRF weaknesses for remediation.

addresses: CWE-918

Outbound connections to external resources can be monitored and limited at the boundary, reducing SSRF impact.

addresses: CWE-918

Validates server-side URLs and resource references to block SSRF attempts.

addresses: CWE-918

Detects server-side request forgery through monitoring of unexpected outbound connections.

References