CVE-2025-64011 Missing authorization in n/a

What is CVE-2025-64011?

CVE-2025-64011 is a medium-severity missing authorization vulnerability in Nextcloud Nextcloud Server, published on 12 Dec 2025. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Nextcloud Server 30.0.0 is vulnerable to an Insecure Direct Object Reference (IDOR) in the /core/preview endpoint. Any authenticated user can access previews of arbitrary files belonging to other users by manipulating the fileId parameter. This allows unauthorized disclosure of sensitive data, such as text files or images, without prior sharing permissions.

Weakness: CWE-639

Which versions are affected by CVE-2025-64011?

It affects 1 product.

Products include Nextcloud Nextcloud Server.

How do I fix CVE-2025-64011?

No fix has been published for CVE-2025-64011 yet. Limit exposure of the affected software until one is available.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2025-64011 being exploited?

There is no known exploitation of CVE-2025-64011 in the wild and no public exploit code.

Other vulnerabilities in Nextcloud Nextcloud Server

• CVE-2021-32802 Preview generation used third-party library not suited for user-generated content in Nextcloud server Critical 9.3
• CVE-2023-26482 Scope of workflow operations is not validated in nextcloud server Critical 9.1
• CVE-2018-3775 Auth bypass in Nextcloud Server High 8.8
• CVE-2023-35172 Nextcloud Server password reset endpoint is not brute force protected High 8.7
• CVE-2023-32320 Nextcloud Server's brute force protection allows someone to send more requests than intended High 8.7

All Nextcloud Nextcloud Server vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-h6j9-6xjq-44c4.