What’s Vulnerable › Vulnerabilities

CVE-2023-28998: Nextcloud Desktop client misbehaves with E2EE when the server returns empty list of metadata keys

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2023-04-04 · updated 2026-06-17
• Weakness: CWE-325

Description

The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server. Starting with version 3.0.0 and prior to version 3.6.5, 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.​ Users should upgrade the Nextcloud Desktop client to 3.6.5 to receive a patch. No known workarounds are available.

Affected products

• Desktop Client: from 3.0.0 before 3.6.5 — fixed in 3.6.5

How to fix

Upgrade to a fixed version: Desktop Client 3.6.5. Check the vendor advisory for mitigations.

References

• https://ethz.ch/content/dam/ethz/special-interest/infk/inst-infsec/appliedcrypto/education/theses/report_DanieleCoppola.pdf
• https://github.com/nextcloud/desktop/pull/5323
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-jh3g-wpwv-cqgr
• https://ethz.ch/content/dam/ethz/special-interest/infk/inst-infsec/appliedcrypto/education/theses/report_DanieleCoppola.pdf
• https://github.com/nextcloud/desktop/pull/5323
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-jh3g-wpwv-cqgr

Get alerted when CVE-2023-28998 or the next vulnerability affects your stack