CVE-2023-39959

MEDIUM 5.3CVE-2023-39959 · Published 10/08/2023 · updated 17/06/2026

In short

CVE-2023-39959 is a MEDIUM (CVSS 5.3) vulnerability affecting nextcloud server (nextcloud).
Chance of exploitation in the next 30 days (EPSS): 0.61%, higher than 49.1% of all vulnerabilities.
Fix: update to 25.0.9, 26.0.4 or later.

Package	Affected versions	Patched versions
nextcloud server nextcloud	`= 27.0.0≥ 25.0.0, < 25.0.9≥ 26.0.0, < 26.0.4`	`25.0.926.0.4`

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.

References

nextcloud/security-advisories security advisory · Vendor Advisory
nextcloud/server#38747 · Patch
hackerone.com/reports/1832126 · Permissions Required

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Package

Affected versions

Patched versions

nextcloud server

nextcloud

= 27.0.0≥ 25.0.0, < 25.0.9≥ 26.0.0, < 26.0.4

25.0.926.0.4

Description

More vulnerabilities in nextcloud server

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