CVE-2023-28999

Name: CVE-2023-28999
Creator: NVD / NIST
Published: 2023-04-04T13:15:09.003+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.4/10EPSS 0.68%

Last modified Jun 17, 2026

CVE-2023-28999 is a medium-severity vulnerability rated 6.4/10 on the CVSS scale. Nextcloud is an open-source productivity platform. In Nextcloud Desktop client 3.0.0 until 3.8.0, Nextcloud Android app 3.13.0 until 3.25.0, and Nextcloud iOS app 3.0.5 until 4.8.0, a malicious server administrator can gain full access to an end-to-end encrypted folder. EPSS estimates a 0.68% chance of exploitation in the next 30 days.

Description

Nextcloud is an open-source productivity platform. In Nextcloud Desktop client 3.0.0 until 3.8.0, Nextcloud Android app 3.13.0 until 3.25.0, and Nextcloud iOS app 3.0.5 until 4.8.0, a malicious server administrator can gain full access to an end-to-end encrypted folder. They can decrypt files, recover the folder structure and add new files. This issue is fixed in Nextcloud Desktop 3.8.0, Nextcloud Android 3.25.0, and Nextcloud iOS 4.8.0. No known workarounds are available.

Metrics

CVSS 3.1

6.4/10

CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:L

EPSS Probability

0.68%

47.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Nextcloud	Desktop	>= 3.0.0, < 3.8.0
Nextcloud	Nextcloud	>= 3.0.5, < 4.8.0
Nextcloud	Nextcloud	>= 3.13.0, < 3.25.0

References

https://ethz.ch/content/dam/ethz/special-interest/infk/inst-infsec/appliedcrypto/education/theses/report_DanieleCoppola.pdfExploit, Technical Description, Third Party Advisory
https://github.com/nextcloud/desktop/pull/5560Patch, Vendor Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-8875-wxww-3rr8Vendor Advisory
https://ethz.ch/content/dam/ethz/special-interest/infk/inst-infsec/appliedcrypto/education/theses/report_DanieleCoppola.pdfExploit, Technical Description, Third Party Advisory
https://github.com/nextcloud/desktop/pull/5560Patch, Vendor Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-8875-wxww-3rr8Vendor Advisory

Timeline

Published: Apr 4, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-28999?

How severe is CVE-2023-28999?

CVE-2023-28999 has a CVSS score of 6.4/10 (MEDIUM severity). The EPSS model estimates a 0.68% probability of exploitation in the next 30 days.

How do I fix CVE-2023-28999?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-28999?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST