{"id":"CVE-2023-39959","aliases":["EUVD-2023-43656","GHSA-g97r-8ffm-hfpj"],"status":"published","title":"Existence of calendars and address books can be checked by unauthenticated users","description":"Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 25.0.0 and prior to versions 25.0.9, 26.0.4, and 27.0.1, unauthenticated users could send a DAV request which reveals whether a calendar or an address book with the given identifier exists for the victim. Nextcloud Server versions 25.0.9, 26.0.4, and 27.0.1 and Nextcloud Enterprise Server versions 25.0.9, 26.0.4, and 27.0.1 contain a patch for this issue. No known workarounds are available.","severity":{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00608,"percentile":0.49404,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-284"],"published":"2023-08-10T17:07:42Z","modified":"2026-10-28T02:30:23Z","products":[{"vendor":"kiteworks","product":"security-advisories"},{"vendor":"nextcloud","product":"nextcloud_server"},{"vendor":"nextcloud","product":"security-advisories"}],"references":[{"url":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-g97r-8ffm-hfpj","tags":["x_refsource_CONFIRM","x_transferred","Vendor Advisory","advisory"]},{"url":"https://github.com/nextcloud/server/pull/38747","tags":["x_refsource_MISC","x_transferred","Patch","fix"]},{"url":"https://hackerone.com/reports/1832126","tags":["x_refsource_MISC","x_transferred","Permissions Required","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/39xxx/CVE-2023-39959.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-39959","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2023-39959","title":"Existence of calendars and address books can be checked by unauthenticated users","description":"Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 25.0.0 and prior to versions 25.0.9, 26.0.4, and 27.0.1, unauthenticated users could send a DAV request which reveals whether a calendar or an address book with the given identifier exists for the victim. Nextcloud Server versions 25.0.9, 26.0.4, and 27.0.1 and Nextcloud Enterprise Server versions 25.0.9, 26.0.4, and 27.0.1 contain a patch for this issue. No known workarounds are available.","status":"published","published":"2023-08-10T17:07:42.367Z","modified":"2024-10-08T14:11:04.848Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low","assessor":"cna"}],"cwes":["CWE-284"],"updated_at":"2026-11-02T14:35:33.138994Z"}],"euvd":[{"id":"EUVD-2023-43656","description":"Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 25.0.0 and prior to versions 25.0.9, 26.0.4, and 27.0.1, unauthenticated users could send a DAV request which reveals whether a calendar or an address book with the given identifier exists for the victim. Nextcloud Server versions 25.0.9, 26.0.4, and 27.0.1 and Nextcloud Enterprise Server versions 25.0.9, 26.0.4, and 27.0.1 contain a patch for this issue. No known workarounds are available.","status":"published","published":"2023-08-10T17:07:42Z","modified":"2024-10-08T14:11:04Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-03T00:27:45.808193Z"}],"nvd":[{"id":"CVE-2023-39959","description":"Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 25.0.0 and prior to versions 25.0.9, 26.0.4, and 27.0.1, unauthenticated users could send a DAV request which reveals whether a calendar or an address book with the given identifier exists for the victim. Nextcloud Server versions 25.0.9, 26.0.4, and 27.0.1 and Nextcloud Enterprise Server versions 25.0.9, 26.0.4, and 27.0.1 contain a patch for this issue. No known workarounds are available.","status":"published","published":"2023-08-10T18:15:10.157Z","modified":"2026-06-17T06:13:02.027Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low","assessor":"secondary"},{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-284"],"updated_at":"2026-11-02T14:08:22.812138Z"}],"osv":[{"id":"CVE-2023-39959","title":"Existence of calendars and address books can be checked by unauthenticated users","description":"Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 25.0.0 and prior to versions 25.0.9, 26.0.4, and 27.0.1, unauthenticated users could send a DAV request which reveals whether a calendar or an address book with the given identifier exists for the victim. Nextcloud Server versions 25.0.9, 26.0.4, and 27.0.1 and Nextcloud Enterprise Server versions 25.0.9, 26.0.4, and 27.0.1 contain a patch for this issue. No known workarounds are available.","status":"published","published":"2023-08-10T17:07:42.367Z","modified":"2026-10-28T02:30:23.612069524Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low"}],"cwes":["CWE-284"],"updated_at":"2026-11-02T15:44:33.244128Z"}]}}