CVE-2021-33509

Plone through 5.2.4 allows remote authenticated managers to perform disk I/O via crafted keyword arguments to the ReStructuredText transform in a Python script.

Published: 2021-05-21 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2021-33509 is rated High Risk (68.3/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 2.04%). Core evidence: EPSS rose +1.19% over the last day, indicating growing attacker interest. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-33509

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.85% 2.04% +1.19%
2 2026-05-23 0.98% 0.85% -0.13%
3 2025-06-01 0.98%

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-33509

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.9 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
3.1 6.0 [email protected]
8.5 2.0 HIGH
AV:N/AC:M/Au:S/C:C/I:C/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:C)
Complete confidentiality impact.
Integrity impact (I:C)
Complete integrity impact.
Availability impact (A:C)
Complete availability impact.
6.8 10.0 [email protected]

Weakness enumeration for CVE-2021-33509

GitHub Security Advisory for CVE-2021-33509

GHSA-hm2p-fhwx-9285 · Severity: critical · Ecosystem: pip — Incorrect Permission Assignment for Critical Resource in Plone

Affected software / configurations for CVE-2021-33509

Vendor Product Version Raw CPE
plone plone <= 5.2.4 cpe:2.3:a:plone:plone:*:*:*:*:*:*:*:*

References for CVE-2021-33509

cvelogic Threat Intelligence