CVE-2023-35928
Change config setting "Allow users to mount external storage" to disabled in "Administration" > "External storage" settings `…/index.php/settings/admin/externalstorages`.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.98%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Nextcloud Server is a space for data storage on Nextcloud, a self-hosted productivity playform. In NextCloud Server versions 25.0.0 until 25.0.7 and 26.0.0 until 26.0.2 and Nextcloud Enterprise Server versions 19.0.0 until 19.0.13.9, 20.0.0 until 20.0.14.14, 21.0.0 until 21.0.9.12, 22.0.0 until 22.2.10.12, 23.0.0 until 23.0.12.7, 24.0.0 until 24.0.12.2, 25.0.0 until 25.0.7, and 26.0.0 until 26.0.2, a user could use this functionality to get access to the login credentials of another user and take over their account. This issue has been patched in Nextcloud Server versions 25.0.7 and 26.0.2 and NextCloud Enterprise Server versions 19.0.13.9, 20.0.14.14, 21.0.9.12, 22.2.10.12, 23.0.12.7, 24.0.12.2, 25.0.7, and 26.0.2. Three workarounds are available. Disable app files_external. Change config setting "Allow users to mount external storage" to disabled in "Administration" > "External storage" settings `…/index.php/settings/admin/externalstorages`. Change config setting to disallow users to create external storages in "Administration" > "External storage" settings `…/index.php/settings/admin/externalstorages` with the types FTP, Nextcloud, SFTP, and/or WebDAV.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.98% probability · 60th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-274
- Affected
- nextcloud/nextcloud server
- Source
- security-advisories@github.com
References
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-637g-xp2c-qh5hVendor Advisory
- https://github.com/nextcloud/server/pull/38265Issue Tracking
- https://hackerone.com/reports/1978882Third Party Advisory
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-637g-xp2c-qh5hVendor Advisory
- https://github.com/nextcloud/server/pull/38265Issue Tracking
- https://hackerone.com/reports/1978882Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.