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TI-2023-26103 Aliases CVE-2023-48239

Nextcloud Server users can make external storage mount points inaccessible for other users

Priority LOW 39CWE-284Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
None · Low · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-284.

Summary

Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 25.0.0 and prior to versions 25.0.13, 26.0.8, and 27.1.3 of Nextcloud Server and starting in version 20.0.0 and prior to versions 20.0.14.16, 21.0.9.13, 22.2.10.15, 23.0.12.12, 24.0.12.8, 25.0.13, 26.0.8, and 27.1.3 of Nextcloud Enterprise Server, a malicious user could update any personal or global external storage, making them inaccessible for everyone else as well. Nextcloud Server 25.0.13, 26.0.8, and 27.1.3 and Nextcloud Enterprise Server is upgraded to 20.0.14.16, 21.0.9.13, 22.2.10.15, 23.0.12.12, 24.0.12.8, 25.0.13, 26.0.8, and 27.1.3 contain a patch for this issue. As a workaround, disable app files_external. This workaround also makes the external storage inaccessible but retains the configurations until a patched version has been deployed.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0095 61st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed security-advisories (nextcloud): 25.0.13, 26.0.8, 27.1.3 +5

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
nextcloudsecurity-advisories25.0.0 to before 25.0.13; 26.0.0 to before 26.0.8; 27.0.0 to before 27.1.3; 20.0.0 to before 20.0.14.16; 21.0.0 to before 21.0.9.13; 22.0.0 to before 22.2.10.15; 23.0.0 to before 23.0.12.12; 24.0.0 to before 24.0.12.825.0.13, 26.0.8, 27.1.3, 20.0.14.16, 21.0.9.13, 22.2.10.15, 23.0.12.12, 24.0.12.8Patch availableCNA
  • security-advisories Vendornextcloud Affected 25.0.0 to before 25.0.13; 26.0.0 to before 26.0.8; 27.0.0 to before 27.1.3; 20.0.0 to before 20.0.14.16; 21.0.0 to before 21.0.9.13; 22.0.0 to before 22.2.10.15; 23.0.0 to before 23.0.12.12; 24.0.0 to before 24.0.12.8 Fixed in 25.0.13, 26.0.8, 27.1.3, 20.0.14.16, 21.0.9.13, 22.2.10.15, 23.0.12.12, 24.0.12.8 Patch available CNA

CPE configurations NVD · 7

CPEVersionsRoleVendor
cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*20.0.0 to before 20.0.14.16; 21.0.0 to before 21.0.9.13; 22.0.0 to before 22.2.10.15; 23.0.0 to before 23.0.12.12; 24.0.0 to before 24.0.12.8Vulnerablenextcloud
cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:*25.0.0 to before 25.0.13Vulnerablenextcloud
cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*25.0.0 to before 25.0.13Vulnerablenextcloud
cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:*26.0.0 to before 26.0.8Vulnerablenextcloud
cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*26.0.0 to before 26.0.8Vulnerablenextcloud
cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:*27.0.0 to before 27.1.3Vulnerablenextcloud
cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:*27.0.0 to before 27.1.3Vulnerablenextcloud
  • cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:* Versions 20.0.0 to before 20.0.14.16; 21.0.0 to before 21.0.9.13; 22.0.0 to before 22.2.10.15; 23.0.0 to before 23.0.12.12; 24.0.0 to before 24.0.12.8 Vulnerable ·nextcloud
  • cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:* Versions 25.0.0 to before 25.0.13 Vulnerable ·nextcloud
  • cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:* Versions 25.0.0 to before 25.0.13 Vulnerable ·nextcloud
  • cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:* Versions 26.0.0 to before 26.0.8 Vulnerable ·nextcloud
  • cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:* Versions 26.0.0 to before 26.0.8 Vulnerable ·nextcloud
  • cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:* Versions 27.0.0 to before 27.1.3 Vulnerable ·nextcloud
  • cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:enterprise:*:*:* Versions 27.0.0 to before 27.1.3 Vulnerable ·nextcloud

Remediation

  • Fix · CNA security-advisories (nextcloud) Fixed in 25.0.13, 26.0.8, 27.1.3, 20.0.14.16, 21.0.9.13, 22.2.10.15, 23.0.12.12, 24.0.12.8

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-48239

References

Exploit 1

Patch 1

Advisory 1

  • TI-2023-20855 Users can delete external storage mount points CVSS 3.1HIGH 7.7
  • TI-2023-11091 Nextcloud download permissions can be changed by resharer CVSS 3.1HIGH 7.5
  • TI-2023-10624 Nextcloud Server vulnerable to SSRF via filter bypass due to lax checking on IPs CVSS 3.1MEDIUM 5.3
  • TI-2025-37238 Cross-site scripting in Nextcloud CVSS 3.1MEDIUM 6.4
  • TI-2023-11086 nextcloud vulnerable to Uncontrolled Resource Consumption CVSS 3.1MEDIUM 6.5
  • TI-2022-18738 Exception logging in Sharepoint app reveals clear-text connection details CVSS 3.1MEDIUM 6.5
See all 188 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences