How severe is CVE-2021-22896?

CVE-2021-22896 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 none, integrity low, and availability none.

Is CVE-2021-22896 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-2021-22896?

CVE-2021-22896 affects Nextcloud. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-22896?

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

When was CVE-2021-22896 published?

CVE-2021-22896 was published on 2021-06-11 and last updated on 2026-06-17.

CVE-2021-22896

CVE-2021-22896 is a medium-severity vulnerability in Nextcloud 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-862.

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-862
Affected product: Nextcloud
Published: 2021-06-11
Last modified: 2026-06-17

Description

Nextcloud Mail before 1.9.5 suffers from improper access control due to a missing permission check allowing other authenticated users to create mail aliases for other users.

Frequently asked questions

What is CVE-2021-22896?: Nextcloud Mail before 1.9.5 suffers from improper access control due to a missing permission check allowing other authenticated users to create mail aliases for other users.
How severe is CVE-2021-22896?: CVE-2021-22896 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 none, integrity low, and availability none.
Is CVE-2021-22896 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-2021-22896?: CVE-2021-22896 affects Nextcloud. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-22896?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-22896 published?: CVE-2021-22896 was published on 2021-06-11 and last updated on 2026-06-17.

References

Affected products (1)

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

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