Home/CVE/The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server. Starting with version 3.0.0 and prior
CVE

CVE-2023-28997

The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server. Starting with version 3.0.0 and prior

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 recover and modify the contents of end-to-end encrypted files. Users should upgrade the Nextcloud Desktop client to 3.6.5 to receive a patch.

No known workarounds are available.

MEDIUM · CVSS 6.7 EPSS 0.00571
Schedule remediation
  • Public exploit or PoC is available
Sigma rules6 YARA rules0
⬡

Weakness Classification

CWE-323Reusing a Nonce, Key Pair in Encryption
▤

Affected Products & Versions

1
nextcloud desktop>= 3.0.0 and < 3.6.5
⚠

Public Exploits & PoCs

1
pocethz.ch · report_DanieleCoppola.pdfethz.ch
◈

Sigma Hunt Rules

6
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
producthighUser Added to Remote Desktop Users Group
producthighNgrok Usage with Remote Desktop Service
productmediumInstallation of TeamViewer Desktop
productmediumDesktop.INI Created by Uncommon Process
productmediumPotential Remote Desktop Tunneling
productmediumNew Remote Desktop Connection Initiated Via Mstsc.EXE
▣

Scoring & Timeline

6.7
MEDIUM · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD04 Apr 2023 · 01:15 PM
CVSS VectorCVSS:3.1/AV:P/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
total
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
🔗

References & Sources

3
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://github.com/nextcloud/desktop/pull/5324Patch
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-4p33-rw27-j5fcVendor Advisory
https://lists.debian.org/debian-lts-announce/2025/09/msg00018.html
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