CVE-2021-3313 json
Plone XSS in User Fullname Property and File Upload
published 2021-05-20 5 y ago modified 2026-06-17 4 mo ago also GHSA-hprr-4vfq-fcxw , PYSEC-2021-78 , EUVD-2021-0188
- cvss
- 5.4
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.0%
- EPSS 1.0% chance of exploitation in 30 days, percentile 62%
- public exploits
- 0
- none known
Summary
Plone CMS until version 5.2.4 has a stored Cross-Site Scripting (XSS) vulnerability in the user fullname property and the file upload functionality. The user's input data is not properly encoded when being echoed back to the user. This data can be interpreted as executable code by the browser and allows an attacker to execute JavaScript in the context of the victim's browser if the victim opens a vulnerable page containing an XSS payload.
Patch / fix
- pypi plone 5.2.4
- plone plone 5.2.4
Exploit prediction
0.98% chance of exploitation in the next 30 days, higher than 62% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- compass-security.com https://www.compass-security.com/fileadmin/Research/Advisories/2021-07_CSNC-2021-013_XSS_in_Plone_CMS.txt 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 |
| GitHub | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | plone | <5.2.4 |
5.2.4 |
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
compass-security.com
/fileadmin/Research/Advisories/2021-07_CSNC-2021-013_XSS_in_Plone_CMS.txt
web, exploit, third-party-advisory
-
plone.org
/download/releases/5.2.3
web, release-notes, vendor-advisory
-
plone.org
/security/hotfix/20210518
web, vendor-advisory
-
openwall.com
/lists/oss-security/2021/05/22/1
mailing-list, web, third-party-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2021-3313
advisory
-
github.com
/plone/Plone
package
-
github.com
/pypa/advisory-database/tree/main/vulns/plone/PYSEC-2021-78.yaml
web
-
plone.org
/security/hotfix/20210518/stored-xss-from-file-upload-svg-html
web
-
plone.org
/security/hotfix/20210518/stored-xss-from-user-fullname
web
-
github.com
/advisories/GHSA-hprr-4vfq-fcxw
advisory
Sources
- CVE List CVE-2021-3313
- GitHub Advisory GHSA-hprr-4vfq-fcxw
- NVD CVE-2021-3313
- OSV PYSEC-2021-78
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