HOMEVULNERABILITIESCVE-2021-33507
MEDIUM

CVE-2021-33507

CWE-79Published: May 21, 2021· Updated: Jun 17, 2026

6.1
CVSS v3.1

Official Description

Zope Products.CMFCore before 2.5.1 and Products.PluggableAuthService before 2.6.2, as used in Plone through 5.2.4 and other products, allow Reflected XSS.

NVD Source

Technical Analysis

CVE-2021-33507 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.

The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.

From a weakness classification perspective (CWE-79): Cross-site scripting (XSS) vulnerabilities allow attackers to inject malicious scripts into web pages viewed by other users.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionRequired
ScopeChanged
Impact
ConfidentialityLow
IntegrityLow
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected Vendors & Products

plone1 product(s)
plone
zope1 product(s)
zope
Source: NVD CPE · 2 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

All References (4)

Quick Facts

CVE IDCVE-2021-33507
CVSS Score6.1 / 10
SeverityMEDIUM
WeaknessCWE-79
CISA KEVNo
Affected2 vendor(s)
PublishedMay 21, 2021

Related CVEs (CWE-79)

Recommended Actions

  • Apply vendor patches immediately
  • Monitor CVE-2021-33507 in threat intel feeds
  • Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.