Low
Existence of calendars and address books can be checked by unauthenticated users
Type: advisorySources: OSV
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2023-39959
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 2 Nov 2026, 20:43 UTC · Revision 1
Source evidence
Existence of calendars and address books can be checked by unauthenticated users
core-osv · Original sourcePublished 10 Aug 2023, 17:07 UTC
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.
osv:CVE-2023-39959
Complete source record
{
"id": "19faf9d4398d2e0440b59f5cc2de4b7d7bd16c2c40ee161259c37a04f759fbad",
"url": "https://osv.dev/vulnerability/CVE-2023-39959",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Existence of calendars and address books can be checked by unauthenticated users",
"summary": "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.",
"evidence": "osv:CVE-2023-39959",
"products": [],
"severity": "low",
"structured": {
"id": "CVE-2023-39959",
"aliases": [
"CVE-2023-39959",
"GHSA-g97r-8ffm-hfpj"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/nextcloud/server",
"type": "GIT",
"events": [
{
"introduced": "20ea9a25353129b56d46951fe7d23939665ab2b2"
},
{
"fixed": "fbc4a4aad97572da902fef0ee61cbd49bba58365"
},
{
"introduced": "62cfd3b4c9ff4d8cdbbe6dcc8b63a1085bb94e3d"
},
{
"fixed": "318ac2714fafa63dcd90805a5cb8ee9d60b58f53"
},
{
"introduced": "add4e4365a4040d2e4e6aa79c0d03c3edd78583c"
},
{
"last_affected": "add4e4365a4040d2e4e6aa79c0d03c3edd78583c"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:*",
"range": [
{
"introduced": "25.0.0"
},
{
"fixed": "25.0.9"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*",
"range": [
{
"introduced": "25.0.0"
},
{
"fixed": "25.0.9"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:*",
"range": [
{
"introduced": "26.0.0"
},
{
"fixed": "26.0.4"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*",
"range": [
{
"introduced": "26.0.0"
},
{
"fixed": "26.0.4"
}
],
"source": "CPE_RANGE"
},
{
"cpe": "cpe:2.3:a:nextcloud:nextcloud_server:27.0.0:*:*:*:-:*:*:*",
"range": [
{
"introduced": "27.0.0"
},
{
"last_affected": "27.0.0"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:nextcloud:nextcloud_server:27.0.0:*:*:*:enterprise:*:*:*",
"range": [
{
"introduced": "27.0.0"
},
{
"last_affected": "27.0.0"
}
],
"source": "CPE_STRING"
}
]
}
}
],
"versions": [
"27.0.0",
"v25.0.9rc2",
"v26.0.4rc2",
"v26.0.4rc1",
"v25.0.9rc1",
"v25.0.8",
"v26.0.3",
"v25.0.8rc2",
"v26.0.3rc2",
"v25.0.8rc1",
"v26.0.3rc1",
"v27.0.0",
"v25.0.7",
"v26.0.2",
"v25.0.7rc1",
"v26.0.2rc1",
"v25.0.6",
"v26.0.1",
"v25.0.6rc1",
"v26.0.1rc1",
"v25.0.5",
"v26.0.0",
"v25.0.5rc1",
"v25.0.4",
"v25.0.4rc1",
"v25.0.3",
"v25.0.3rc2",
"v25.0.3rc1",
"v25.0.2",
"v25.0.2rc3",
"v25.0.2rc2",
"v25.0.2rc1",
"v25.0.1",
"v25.0.1rc1",
"v25.0.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-39959.json"
}
}
],
"modified": "2026-10-28T02:30:23.612069524Z",
"provider": "osv",
"references": [
"https://hackerone.com/reports/1832126",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/39xxx/CVE-2023-39959.json",
"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-g97r-8ffm-hfpj",
"https://nvd.nist.gov/vuln/detail/CVE-2023-39959",
"https://github.com/nextcloud/server/pull/38747"
],
"provider_metadata": {
"cwe_ids": [
"CWE-284"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/39xxx/CVE-2023-39959.json"
}
},
"related_cves": [
{
"value": "CVE-2023-39959",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 489985,
"published_at": "2023-08-10T17:07:42.367+00:00"
}