CVE-2025-66549

Nextcloud Desktop discloses information when attempting to lock a file inside a end-to-end encrypted directory

2.4 LowFix available

Nextcloud Desktop is the desktop sync client for Nextcloud. Prior to 3.16.5, when trying to manually lock a file inside an end-to-end encrypted directory, the path of the file was sent to the server unencrypted, making it possible for administrators to see it in log files. This vulnerability is fixed in 3.16.5.

Attack profile

How easy it is to exploit

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

What an attacker can affect

Confidentiality: Low
Integrity: None
Availability: None

Exploit likelihood

0.32%Up 0.3 points since Dec 6, 2025

What each source reports

CVE List Score used 2.4

Nextcloud Desktop discloses information when attempting to lock a file inside a end-to-end encrypted directory

Record: CVE-2025-66549
CVSS 3.1: 2.4 LowCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:N/A:N
Weakness: CWE-209
Updated: 2026-11-02

EUVDEUVD-2025-201462 2.4

Record: EUVD-2025-201462
CVSS 3.1: 2.4 LowCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:N/A:N
Updated: 2026-11-02

NVD 2.4

Record: CVE-2025-66549
CVSS 3.1: 2.4 LowCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:N/A:N
CVSS 3.1: 2.7 LowCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N
Weakness: CWE-209
Updated: 2026-11-02

OSV 2.4

Nextcloud Desktop discloses information when attempting to lock a file inside a end-to-end encrypted directory

Record: CVE-2025-66549
CVSS 3.1: 2.4 LowCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:N/A:N
Weakness: CWE-209
Updated: 2026-11-02

OSVDEBIAN-CVE-2025-66549 2.7

Record: DEBIAN-CVE-2025-66549
CVSS 3.1: 2.7 LowCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N
Updated: 2026-11-02

OSVUBUNTU-CVE-2025-66549 2.4

Record: UBUNTU-CVE-2025-66549
CVSS 3.1: 2.4 LowCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:N/A:N
CVSS 3.1: 2.7 LowCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`nextcloud-desktop` Debian:12	All versions, plus listed versions 3.10.0-13.11.0-13.11.0-1.13.11.0-1.1~exp13.13.2-1 Show 28 moreShow less 3.13.2-23.14.1-13.15.0-13.15.2-13.15.2-23.15.3-13.16.0-13.16.2-13.16.4-13.16.6-13.16.6-23.16.6-33.16.7-13.16.7-1~deb13u13.7.3-13.7.3-1+deb12u13.7.3-1+deb12u23.9.0-133.0.0-133.0.0-233.0.2-133.0.2-233.0.2-333.0.7-14.0.1-14.0.1-24.0.1-34.0.6-1	None known
`nextcloud-desktop` Debian:13	before 3.16.6-3, plus listed versions 3.16.4-13.16.6-13.16.6-2	3.16.6-3
`nextcloud-desktop` Debian:14	before 3.16.6-3, plus listed versions 3.16.4-13.16.6-13.16.6-2	3.16.6-3
`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
`nextcloud-desktop` Ubuntu:24.04:LTS	All versions, plus listed versions 3.9.0-13.10.0-13.11.0-13.11.0-1.1build33.11.0-1.1build4	None known

History

History
Recorded	Changed	Sources
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-2025-66549 is a low vulnerability (CVSS 2.4) in Nextcloud Desktop, published December 5, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.32%, the 24th percentile. Fixed in nextcloud-desktop 3.16.6-3.