CVE-2021-3313
Plone XSS in User Fullname Property and File Upload
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
5.4
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.
- Record
CVE-2021-3313- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - CVSS 2.0
- 3.5 Low
AV:N/AC:M/Au:S/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2021-3313- Updated
- 2026-11-02
EUVDEUVD-2021-0188 No score
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.
- Record
EUVD-2021-0188- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-hprr-4vfq-fcxw
5.3
Plone XSS in User Fullname Property and File Upload
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.
- Record
GHSA-hprr-4vfq-fcxw- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
5.4
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.
- Record
CVE-2021-3313- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-hprr-4vfq-fcxw
5.3
Plone XSS in User Fullname Property and File Upload
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.
- Record
GHSA-hprr-4vfq-fcxw- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSVPYSEC-2021-78 No score
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.
- Record
PYSEC-2021-78- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
plonePyPI |
before 5.2.4 | 5.2.4 |
plonePyPI |
before 5.2.4, plus listed versions 3.23.2.13.2.23.2.33.2a1 Show 45 moreShow less3.2rc13.33.3.13.3.23.3.33.3.43.3.53.3.63.3b13.3rc13.3rc23.3rc33.3rc43.3rc54.04.0.14.0.104.0.24.0.34.0.44.0.54.0.64.0.74.0.84.0.94.0a14.0a24.0a34.0a44.0a54.0b14.0b24.0b34.0b44.0b54.0rc14.14.1.14.1.24.1.34.1.44.1.54.1.64.1a14.1a2 |
5.2.4 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-3313 is a medium vulnerability (CVSS 5.4) in Plone, published May 20, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.98%, the 62nd percentile. Fixed in plone 5.2.4.
References
plone.org/download/releases/5.2.3
compass-security.com/fileadmin/Research/Advisories/2021-07_CSNC-2021-013_XSS_in_Plone_CMS.txt
plone.org/security/hotfix/20210518
openwall.com/lists/oss-security/2021/05/22/1
nvd.nist.gov/vuln/detail/CVE-2021-3313
plone.org/security/hotfix/20210518/stored-xss-from-file-upload-svg-html
Left out here: 94 versions. The JSON record has them.