How severe is CVE-2020-28645?

CVE-2020-28645 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2020-28645 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-28645?

CVE-2020-28645 affects Owncloud. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-28645?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2020-28645 published?

CVE-2020-28645 was published on 2021-02-09 and last updated on 2026-06-17.

CVE-2020-28645

CVE-2020-28645 is a critical-severity vulnerability in Owncloud with a CVSS 3.x base score of 9.1. 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: Critical (CVSS 3.x base score 9.1)
CVSS v2: 5.0
EPSS exploit prediction: 1% (66th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Owncloud
Published: 2021-02-09
Last modified: 2026-06-17

Description

Deleting users with certain names caused system files to be deleted. Risk is higher for systems which allow users to register themselves and have the data directory in the web root. This affects ownCloud/core versions < 10.6.

Frequently asked questions

What is CVE-2020-28645?: Deleting users with certain names caused system files to be deleted. Risk is higher for systems which allow users to register themselves and have the data directory in the web root. This affects ownCloud/core versions < 10.6.
How severe is CVE-2020-28645?: CVE-2020-28645 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2020-28645 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (66th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-28645?: CVE-2020-28645 affects Owncloud. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-28645?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2020-28645 published?: CVE-2020-28645 was published on 2021-02-09 and last updated on 2026-06-17.

References

https://owncloud.com/security-advisories/missing-user-validation-leading-to-information-disclosure/

Affected products (1)

cpe:2.3:a:owncloud:owncloud:*:*:*:*:*:*:*:*

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