How severe is CVE-2021-33510?

CVE-2021-33510 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2021-33510 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-33510?

CVE-2021-33510 affects Plone. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-33510?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-33510 published?

CVE-2021-33510 was published on 2021-05-21 and last updated on 2026-06-17.

CVE-2021-33510

CVE-2021-33510 is a medium-severity vulnerability in Plone with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-918.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
CVSS v2: 4.0
EPSS exploit prediction: 1% (58th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-918
Affected product: Plone
Published: 2021-05-21
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-33510?: 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.
How severe is CVE-2021-33510?: CVE-2021-33510 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2021-33510 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-33510?: CVE-2021-33510 affects Plone. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-33510?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-33510 published?: CVE-2021-33510 was published on 2021-05-21 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:plone:plone:*:*:*:*:*:*:*:*

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