Security Resilience

CVE-2023-35928

Nextcloud Server 19.0.0 – 19.0.13.9

Published
23 June 2023
Modified
21 November 2024
Patch / advisory
CVSS Score v3.1 8.4
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H
EPSS Score 0.0098 61th percentile
Risk Priority 57 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-35928 is a high-severity Improper Handling of Insufficient Privileges (CWE-274) vulnerability in Nextcloud Nextcloud Server. Its CVSS base score is 8.4 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Junk Data (T1001.001); ranked in the top 39% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001.001 Junk Data Command And Control
Adversaries may add junk data to protocols used for command and control to make detection more difficult.
T1001.002 Steganography Command And Control
Adversaries may use steganographic techniques to hide command and control traffic to make detection efforts more difficult.
T1008 Fallback Channels Command And Control
Adversaries may use fallback or alternate communication channels if the primary channel is compromised or inaccessible in order to maintain reliable command and control and to avoid data transfer thresholds.
T1011.001 Exfiltration Over Bluetooth Exfiltration
Adversaries may attempt to exfiltrate data over Bluetooth rather than the command and control channel.
T1012 Query Registry Discovery
Adversaries may interact with the Windows Registry to gather information about the system, configuration, and installed software.
T1016 System Network Configuration Discovery Discovery
Adversaries may look for details about the network configuration and settings, such as IP and/or MAC addresses, of systems they access or through information discovery of remote systems.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-52523Same product: Nextcloud Nextcloud Server
CVE-2023-48306Same product: Nextcloud Nextcloud Server
CVE-2023-32318Same product: Nextcloud Nextcloud Server
CVE-2024-52519Same product: Nextcloud Nextcloud Server
CVE-2023-49792Same product: Nextcloud Nextcloud Server
CVE-2023-28833Same product: Nextcloud Nextcloud Server
CVE-2023-39963Same product: Nextcloud Nextcloud Server
CVE-2024-52514Same product: Nextcloud Nextcloud Server
CVE-2023-25161Same product: Nextcloud Nextcloud Server
CVE-2023-48239Same product: Nextcloud Nextcloud Server

Affected Assets

nextcloud
nextcloud server
19.0.0 — 19.0.13.9 · 20.0.0 — 20.0.14.14 · 21.0.0 — 21.0.9.12

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

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Detect
Catch it (NIST detect / respond)

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Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

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Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 partial match
blocks

Enforcing least-privilege access policies directly prevents improper handling of insufficient privileges.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

blocks

A.5.15 only requires defining a topic-specific access control policy and determining requirements; it does not itself enforce authorizations or handle insufficient-privilege cases at runtime, so the weakness can still be exploited (per the owner's labeling rule: policy/dependency controls do not prevent unless other controls act on them).

blocks

Access-rights provisioning and review reduce privilege gaps, yet do not address the software’s failure to handle insufficient privileges gracefully.

blocks

Privileged-access-rights control directly limits the situations in which insufficient privileges can occur.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).

Oracle Linux 9 (2 rules)
  • V-271452 OL 9 must use a Linux Security Module configured to enforce limits on system services. blocks CWE-274
  • V-271640 OL 9 must be configured so that the Network File System (NFS) is configured to use RPCSEC_GSS. blocks CWE-274
RHEL 9 (1 rule)
  • V-258078 RHEL 9 must use a Linux Security Module configured to enforce limits on system services. blocks CWE-274

References