Calendar and address-book enumeration via late permission check
Published Aug 10, 2023 · Updated Oct 8, 2024
Improper access control in Nextcloud Server allows remote attackers to disclose whether specified DAV calendars or address books exist. The DAV MKCOL handler checks for an existing calendar or address-book identifier before rejecting requests lacking write permission on the parent collection, producing distinguishable responses. No authentication is required; disclosure is limited to resource existence rather than calendar entries, contacts, or other contents.
Summary
What happened
Improper access control in Nextcloud Server allows remote attackers to disclose whether specified DAV calendars or address books exist. The DAV MKCOL handler checks for an existing calendar or address-book identifier before rejecting requests lacking write permission on the parent collection, producing distinguishable responses. No authentication is required; disclosure is limited to resource existence rather than calendar entries, contacts, or other contents.
The record
- CVE
- CVE-2023-39959
- Published
- Aug 10, 2023
- Updated
- Oct 8, 2024
- Vendor
- Nextcloud GmbH
- Product
- Security Advisories
- Classifications
- CWE-284, T1595
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 10, 2023CVE publishedPublication date reported by the CVE source.
- Oct 8, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 25.0.0, < 25.0.9
- Affected versionversion=>= 26.0.0, < 26.0.4
- Affected versionversion=>= 27.0.0, < 27.0.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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