How severe is CVE-2021-39220?

CVE-2021-39220 has a CVSS 3.x base score of 3.5, rated low severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2021-39220 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39220?

CVE-2021-39220 affects Nextcloud Mail. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-39220?

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

When was CVE-2021-39220 published?

CVE-2021-39220 was published on 2021-10-25 and last updated on 2026-06-17.

CVE-2021-39220

CVE-2021-39220 is a low-severity vulnerability in Nextcloud Mail with a CVSS 3.x base score of 3.5. 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-20.

Key facts

Severity: Low (CVSS 3.x base score 3.5)
CVSS v2: 3.5
EPSS exploit prediction: 1% (51st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Nextcloud Mail
Published: 2021-10-25
Last modified: 2026-06-17

Description

Nextcloud is an open-source, self-hosted productivity platform The Nextcloud Mail application prior to versions 1.10.4 and 1.11.0 does by default not render images in emails to not leak the read state or user IP. The privacy filter failed to filter images with a relative protocol. It is recommended that the Nextcloud Mail application is upgraded to 1.10.4 or 1.11.0. There are no known workarounds aside from upgrading.

Frequently asked questions

What is CVE-2021-39220?: Nextcloud is an open-source, self-hosted productivity platform The Nextcloud Mail application prior to versions 1.10.4 and 1.11.0 does by default not render images in emails to not leak the read state or user IP. The privacy filter failed to filter images with a relative protocol. It is recommended that the Nextcloud Mail application is upgraded to 1.10.4 or 1.11.0. There are no known workarounds aside from upgrading.
How severe is CVE-2021-39220?: CVE-2021-39220 has a CVSS 3.x base score of 3.5, rated low severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2021-39220 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (51st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39220?: CVE-2021-39220 affects Nextcloud Mail. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-39220?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-39220 published?: CVE-2021-39220 was published on 2021-10-25 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:nextcloud:mail:*:*:*:*:*:*:*:*

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