Plone XSS Vulnerability

published 2021-03-24 5 y ago modified 2026-06-17 4 mo ago also GHSA-38g6-x6jv-jwff , PYSEC-2021-889 , EUVD-2021-0196

cvss: 5.4; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.8%; EPSS 0.8% chance of exploitation in 30 days, percentile 55%
public exploits: 0; none known

A stored cross-site scripting (XSS) vulnerability in Plone CMS 5.2.3 exists in site-controlpanel via the "form.widgets.site_title" parameter.

Exploit prediction

0.76% chance of exploitation in the next 30 days, higher than 55% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

exploit-db.com https://www.exploit-db.com/exploits/49668 referenced PoC, tagged "exploit" by a source, unverified
github.com https://github.com/plone/Products.CMFPlone/issues/3255 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
NVD	2.0	3.5	AV:N/AC:M/Au:S/C:N/I:P/A:N
OSV	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem	package	affected	fixed in
pypi	plone	<=5.2.3	no fix listed

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

exploit-db.com /exploits/49668
web, exploit, third-party-advisory, vdb-entry, advisory
github.com /plone/Products.CMFPlone/issues/3255
web, exploit, issue-tracking, third-party-advisory, report
nvd.nist.gov /vuln/detail/CVE-2021-29002
advisory
github.com /plone/Plone
package
github.com /pypa/advisory-database/tree/main/vulns/plone/PYSEC-2021-889.yaml
web

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary