CVE-2021-32654 Attacker can obtain write access to any federated share/public link

What is CVE-2021-32654?

CVE-2021-32654 is a high-severity missing authorization vulnerability in Nextcloud Nextcloud Server, published on 1 Jun 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.11, 20.0.10, and 21.0.2, an attacker is able to receive write/read privileges on any Federated File Share. Since public links can be added as federated file share, this can also be exploited on any public link. Users can upgrade to patched versions (19.0.11, 20.0.10 or 21.0.2) or, as a workaround, disable federated file sharing.

Weakness: CWE-639

Which versions are affected by CVE-2021-32654?

It affects 1 product.

Products include Nextcloud Nextcloud Server.

How do I fix CVE-2021-32654?

No fix has been published for CVE-2021-32654 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-2021-32654 being exploited?

There is no known exploitation of CVE-2021-32654 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-jf9h-v24c-22g5.