CVE-2021-33510
Server-Side Request Forgery in Plone
Plone through 5.2.4 allows remote authenticated managers to conduct SSRF attacks via an event ical URL, to read one line of a file.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
Plone through 5.2.4 allows remote authenticated managers to conduct SSRF attacks via an event ical URL, to read one line of a file.
- Record
CVE-2021-33510- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - CVSS 2.0
- 4.0 Medium
AV:N/AC:L/Au:S/C:P/I:N/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
CVE List No score
Plone through 5.2.4 allows remote authenticated managers to conduct SSRF attacks via an event ical URL, to read one line of a file.
- Record
CVE-2021-33510- Updated
- 2026-11-02
EUVDEUVD-2021-0192 No score
Plone through 5.2.4 allows remote authenticated managers to conduct SSRF attacks via an event ical URL, to read one line of a file.
- Record
EUVD-2021-0192- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-4mg4-wvmx-5332
Server-Side Request Forgery in Plone
Plone through 5.2.4 allows remote authenticated managers to conduct SSRF attacks via an event ical URL, to read one line of a file.
- Record
GHSA-4mg4-wvmx-5332- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
OSV
Plone through 5.2.4 allows remote authenticated managers to conduct SSRF attacks via an event ical URL, to read one line of a file.
- Record
CVE-2021-33510- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Updated
- 2026-11-02
OSVGHSA-4mg4-wvmx-5332
Server-Side Request Forgery in Plone
Plone through 5.2.4 allows remote authenticated managers to conduct SSRF attacks via an event ical URL, to read one line of a file.
- Record
GHSA-4mg4-wvmx-5332- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N - Weakness
- CWE-918
- Updated
- 2026-11-02
OSVPYSEC-2021-82 No score
Plone through 5.2.4 allows remote authenticated managers to conduct SSRF attacks via an event ical URL, to read one line of a file.
- Record
PYSEC-2021-82- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
plonePyPI |
through 5.2.4 | None known |
plonePyPI |
through 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 |
None known |
plonePyPI |
before 5.2.5, 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 |
5.2.5 |
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-2021-33510 is a medium vulnerability (CVSS 4.3) in Plone, published May 21, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.96%, the 61st percentile. Fixed in plone 5.2.5.
References
plone.org/security/hotfix/20210518/server-side-request-forgery-via-event-ical-url
openwall.com/lists/oss-security/2021/05/22/1
nvd.nist.gov/vuln/detail/CVE-2021-33510
github.com/advisories/GHSA-4mg4-wvmx-5332
Left out here: 189 versions. The JSON record has them.