How severe is CVE-2023-28833?

CVE-2023-28833 has a CVSS 3.x base score of 2.4, rated low severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2023-28833 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-2023-28833?

CVE-2023-28833 primarily affects Nextcloud Nextcloud Server. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-28833?

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

When was CVE-2023-28833 published?

CVE-2023-28833 was published on 2023-03-30 and last updated on 2026-06-17.

CVE-2023-28833

CVE-2023-28833 is a low-severity vulnerability in Nextcloud Nextcloud Server with a CVSS 3.x base score of 2.4. 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-434.

Key facts

Severity: Low (CVSS 3.x base score 2.4)
EPSS exploit prediction: 1% (51st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-434
Affected product: Nextcloud Nextcloud Server
Published: 2023-03-30
Last modified: 2026-06-17

Description

Nextcloud server is an open source home cloud implementation. In affected versions admins of a server were able to upload a logo or a favicon and to provided a file name which was not restricted and could overwrite files in the appdata directory. Administrators may have access to overwrite these files by other means but this method could be exploited by tricking an admin into uploading a maliciously named file. It is recommended that the Nextcloud Server is upgraded to 24.0.10 or 25.0.4. Users unable to upgrade should avoid ingesting logo files from untrusted sources.

Frequently asked questions

What is CVE-2023-28833?: Nextcloud server is an open source home cloud implementation. In affected versions admins of a server were able to upload a logo or a favicon and to provided a file name which was not restricted and could overwrite files in the appdata directory. Administrators may have access to overwrite these files by other means but this method could be exploited by tricking an admin into uploading a maliciously named file. It is recommended that the Nextcloud Server is upgraded to 24.0.10 or 25.0.4. Users unable to upgrade should avoid ingesting logo files from untrusted sources.
How severe is CVE-2023-28833?: CVE-2023-28833 has a CVSS 3.x base score of 2.4, rated low severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2023-28833 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-2023-28833?: CVE-2023-28833 primarily affects Nextcloud Nextcloud Server. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-28833?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2023-28833 published?: CVE-2023-28833 was published on 2023-03-30 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*
cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:*

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