A notable security flaw has been identified in Nextcloud Server, an open-source platform for content collaboration. This vulnerability, tracked as CVE-2026-45283, specifically affects the This vulnerability impacts specific versions of Nextcloud Server and Nextcloud Enterprise Server:<\/p>\n The vulnerability has been thoroughly analyzed by Nextcloud. Patches and updated versions addressing this issue have been released to ensure the security of user files and data integrity.<\/p>\n This vulnerability is rated as Medium<\/strong> severity with a CVSS score of 6.3. While it requires an authenticated user to exploit, the ability for an attacker to manipulate file locks and potentially disrupt file access for other users, or even disclose lock tokens, poses a significant risk to data availability and integrity within a Nextcloud instance. It could lead to unauthorized modifications or denial of service for legitimate users trying to access their files.<\/p>\n To mitigate the risk associated with CVE-2026-45283, Nextcloud strongly recommends upgrading your server immediately:<\/p>\n Regularly applying security updates is crucial to maintaining the integrity and security of your Nextcloud environment.<\/p>\n https:\/\/github.com\/nextcloud\/files_lock\/pull\/1007 Overview A notable security flaw has been identified in Nextcloud Server, an open-source platform for content collaboration. This vulnerability, tracked as CVE-2026-45283, specifically affects the files_lock application. It allowed authenticated users to bypass normal ownership checks when handling file lock and unlock requests via WebDAV. This meant an attacker could gain unauthorized control over other […]<\/p>\n","protected":false},"author":17,"featured_media":2652,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[724,1127,770,779,1126],"class_list":["post-3648","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-security","tag-data-integrity","tag-file-security","tag-nextcloud","tag-server-security","tag-webdav"],"blocksy_meta":[],"yoast_head":"\nfiles_lock<\/code> application. It allowed authenticated users to bypass normal ownership checks when handling file lock and unlock requests via WebDAV. This meant an attacker could gain unauthorized control over other users’ files, potentially locking or unlocking them without permission. Furthermore, the vulnerability exposed sensitive lock tokens in error messages, enabling attackers to remove existing token-based locks placed by legitimate client applications.<\/p>\nCVE Details<\/h2>\n
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Affected Products<\/h2>\n
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Current Status<\/h2>\n
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References<\/h2>\n
https:\/\/github.com\/nextcloud\/security-advisories\/security\/advisories\/GHSA-4chh-6mhf-p4jj
https:\/\/hackerone.com\/reports\/3301553#<\/p>\n","protected":false},"excerpt":{"rendered":"