CVE-2023-48239

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

HIGH

7.1

CVSS Score

Published: November 21, 2023 at 09:02 PM UTC

Updated: June 17, 2026 at 06:33 AM UTC

1 product affected across 1 vendorNextcloud/server

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Severity

HIGH7.1

Exploit prediction

EPSS 0.9%

SSVC

No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Nextcloud/server · Nextcloudnextcloud-app

95%

20.0.0 ≤ v < 20.0.14.1621.0.0 ≤ v < 21.0.9.1322.0.0 ≤ v < 22.2.10.1523.0.0 ≤ v < 23.0.12.1224.0.0 ≤ v < 24.0.12.825.0.0 ≤ v < 25.0.1326.0.0 ≤ v < 26.0.827.0.0 ≤ v < 27.1.3

Affected range stops below 20.0.14.16, so it looks safe — our inference, not a vendor statement

Affected range stops below 21.0.9.13, so it looks safe — our inference, not a vendor statement

Affected range stops below 22.2.10.15, so it looks safe — our inference, not a vendor statement

Affected range stops below 23.0.12.12, so it looks safe — our inference, not a vendor statement

Affected range stops below 24.0.12.8, so it looks safe — our inference, not a vendor statement

Affected range stops below 25.0.13, so it looks safe — our inference, not a vendor statement

Affected range stops below 26.0.8, so it looks safe — our inference, not a vendor statement

Affected range stops below 27.1.3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (3)

x_refsource_CONFIRMVendor Advisory

Source: [email protected]

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f962-hw26-g267

x_refsource_MISCPatch

Source: [email protected]

https://github.com/nextcloud/server/pull/41123

x_refsource_MISCExploit

Source: [email protected]

https://hackerone.com/reports/2212627

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.1HIGH[email protected]

Attack Vector: NETWORK
Complexity: LOW
Privileges: LOW
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: NONE
Integrity: LOW
Availability: HIGH

Vector?

Quick Info

StatusMODIFIED

CWE

CWE-284NVD-CWE-Other

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