CVE-2023-35928 | Nextcloud user scoped external storage can be used to gather credentials of other users

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.

Published: 2023-06-23 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-35928 is rated Moderate Risk (56/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.46%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-35928

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-18 0.36% 0.46% +0.09%
2 2026-03-04 0.14% 0.36% +0.22%
3 2026-03-01 — 0.14% —

Full EPSS history (43 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-35928

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.4 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.7 6.0 [email protected]
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]

Weakness enumeration for CVE-2023-35928

Affected software / configurations for CVE-2023-35928

Vendor Product Version Raw CPE
nextcloud nextcloud_server >= 19.0.0, < 19.0.13.9 cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*
nextcloud nextcloud_server >= 20.0.0, < 20.0.14.14 cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*
nextcloud nextcloud_server >= 21.0.0, < 21.0.9.12 cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*
nextcloud nextcloud_server >= 22.0.0, < 22.2.10.12 cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*
nextcloud nextcloud_server >= 23.0.0, < 23.0.12.7 cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*
nextcloud nextcloud_server >= 24.0.0, < 24.0.12.2 cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*
nextcloud nextcloud_server >= 25.0.0, < 25.0.7 cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:*
nextcloud nextcloud_server >= 25.0.0, < 25.0.7 cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*
nextcloud nextcloud_server >= 26.0.0, < 26.0.2 cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:*
nextcloud nextcloud_server >= 26.0.0, < 26.0.2 cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*

References for CVE-2023-35928

cvelogic Threat Intelligence