CVE-2023-28997

Nextcloud Desktop: Initialization vector reuse in E2EE allows malicious server admin to break, manipulate, access files

6.7 MediumFix available

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.

Attack profile

How easy it is to exploit

Attack vector: Physical
Complexity: Low
Privileges needed: High
User interaction: Required

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: None

Exploit likelihood

1.07%Up 1.0 points since Apr 5, 2023

What each source reports

CVE List Score used 6.7

Nextcloud Desktop: Initialization vector reuse in E2EE allows malicious server admin to break, manipulate, access files

Record: CVE-2023-28997
CVSS 3.1: 6.7 MediumCVSS:3.1/AV:P/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N
Weakness: CWE-323
Updated: 2026-11-02

EUVDEUVD-2023-32615 6.7

Record: EUVD-2023-32615
CVSS 3.1: 6.7 MediumCVSS:3.1/AV:P/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N
Updated: 2026-11-02

NVD 6.7

Record: CVE-2023-28997
CVSS 3.1: 6.7 MediumCVSS:3.1/AV:P/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
Weakness: CWE-323
Updated: 2026-11-02

OSVALPINE-CVE-2023-28997 6.5

Record: ALPINE-CVE-2023-28997
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
Updated: 2026-11-03

OSV 6.7

Nextcloud Desktop: Initialization vector reuse in E2EE allows malicious server admin to break, manipulate, access files

Record: CVE-2023-28997
CVSS 3.1: 6.7 MediumCVSS:3.1/AV:P/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N
Weakness: CWE-323
Updated: 2026-11-02

OSVDEBIAN-CVE-2023-28997 6.5

Record: DEBIAN-CVE-2023-28997
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
Updated: 2026-11-02

OSVUBUNTU-CVE-2023-28997 6.7

Record: UBUNTU-CVE-2023-28997
CVSS 3.1: 6.7 MediumCVSS:3.1/AV:P/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`nextcloud-client` Alpine:v3.18	before 3.6.6-r0	3.6.6-r0
`nextcloud-client` Alpine:v3.19	before 3.6.6-r0	3.6.6-r0
`nextcloud-client` Alpine:v3.20	before 3.6.6-r0	3.6.6-r0
`nextcloud-client` Alpine:v3.21	before 3.6.6-r0	3.6.6-r0
`nextcloud-client` Alpine:v3.22	before 3.6.6-r0	3.6.6-r0
`nextcloud-client` Alpine:v3.23	before 3.6.6-r0	3.6.6-r0
`nextcloud-client` Alpine:v3.24	before 3.6.6-r0	3.6.6-r0
`nextcloud-desktop` Debian:12	before 3.7.0-1	3.7.0-1
`nextcloud-desktop` Debian:13	before 3.7.0-1	3.7.0-1
`nextcloud-desktop` Debian:14	before 3.7.0-1	3.7.0-1
`nextcloud-desktop` Debian:11	before 3.1.1-2+deb11u2, plus listed versions 3.1.1-23.1.1-2+deb11u1	3.1.1-2+deb11u2
`nextcloud-desktop` Ubuntu:20.04:LTS	All versions, plus listed versions 2.5.3-12.6.0-12.6.1-12.6.1-22.6.2-12.6.2-1build1	None known
`nextcloud-desktop` Ubuntu:22.04:LTS	All versions, plus listed versions 3.2.3-0ubuntu13.3.5-13.3.5-1ubuntu13.4.2-13.4.2-1ubuntu1	None known

History

History
Recorded	Changed	Sources
Nov 3, 2026	affected, aliases, references	OSV
Nov 2, 2026	first indexed	CVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2023-28997 is a medium vulnerability (CVSS 6.7) in Nextcloud Desktop, published April 4, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.07%, the 64th percentile. Fixed in nextcloud-client 3.6.6-r0.

References

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