CVE-2023-39959: Existence of calendars and address books can be checked by unauthenticated users
First published: Thu Aug 10 2023(Updated: )
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.
Credit: security-advisories@github.com security-advisories@github.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Nextcloud Nextcloud Server | >=25.0.0<25.0.9 | |
| Nextcloud Nextcloud Server | >=25.0.0<25.0.9 | |
| Nextcloud Nextcloud Server | >=26.0.0<26.0.4 | |
| Nextcloud Nextcloud Server | >=26.0.0<26.0.4 | |
| Nextcloud Nextcloud Server | =27.0.0 | |
| Nextcloud Nextcloud Server | =27.0.0 |
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Reference Links
Frequently Asked Questions
What is CVE-2023-39959?
CVE-2023-39959 is a vulnerability in Nextcloud Server that allows unauthenticated users to reveal whether a calendar or address book with a specific identifier exists.
What is the severity of CVE-2023-39959?
The severity of CVE-2023-39959 is medium with a CVSS score of 5.3.
Which versions of Nextcloud Server are affected by CVE-2023-39959?
Nextcloud Server versions 25.0.0 to 25.0.9, 26.0.0 to 26.0.4, and 27.0.0 are affected by CVE-2023-39959.
How can unauthenticated users exploit CVE-2023-39959?
Unauthenticated users can exploit CVE-2023-39959 by sending a DAV request to determine the existence of a calendar or address book.
Are there any fixes available for CVE-2023-39959?
Yes, fixes for CVE-2023-39959 are available in versions 25.0.9, 26.0.4, and 27.0.1 of Nextcloud Server.
- collector/nvd-api
- collector/nvd-index
- agent/author
- agent/type
- agent/softwarecombine
- collector/mitre-cve
- source/MITRE
- agent/weakness
- agent/remedy
- agent/last-modified-date
- agent/title
- agent/severity
- agent/references
- agent/description
- agent/tags
- agent/first-publish-date
- agent/event
- vendor/nextcloud
- canonical/nextcloud nextcloud server
- version/nextcloud nextcloud server/25.0.0
- version/nextcloud nextcloud server/26.0.0
- version/nextcloud nextcloud server/27.0.0