Medium severity · published Jun 1, 2026
CVE-2026-45283
Nextcloud: Files Lock app allows users to lock and unlock files of other users
4.3
CVSS
0.2%
EPSS
No
On KEV
Description
Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.2, and 33.0.0 to before 33.0.1, the files_lock app did not properly validate the ownership of files when processing DAV lock and unlock requests. An authenticated user could lock or unlock files belonging to other users by targeting their absolute WebDAV paths. Additionally, lock tokens were disclosed to unauthorized callers in error responses, allowing attackers to remove token-based locks placed by other users' client applications. It is recommended that the Nextcloud Server is upgraded to 32.0.2 or 33.0.1. It is recommended that the Nextcloud Enterprise Server is upgraded to 31.0.14.4 or 32.0.2 or 33.0.1
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 11% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SE
security-advisories · nextcloud
>= 32.0.0, < 32.0.2; >= 33.0.0, < 33.0.1 · source: vendor
NS
Nextcloud Server · Nextcloud
32.0.0 before 32.0.2; 33.0.0 before 33.0.1; 31.0.0 before 31.0.14.4; 32.0.0 before 32.0.2; 33.0.0 before 33.0.1 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-45283
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-45283
Issue Tracking
https://github.com/nextcloud/files_lock/pull/1007
Vendor Advisory
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-4chh-6mhf-p4jj
Permissions Required
https://hackerone.com/reports/3301553#
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