Nextcloud Server up to 32.0.8/33.0.2 improper authentication

Summaryinfo

A vulnerability was found in Nextcloud Server up to 32.0.8/33.0.2. It has been classified as critical. This affects an unknown part. Performing a manipulation results in improper authentication. This vulnerability was named CVE-2026-45690. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability, which was classified as critical, was found in Nextcloud Server up to 32.0.8/33.0.2. This affects an unknown code block. The manipulation with an unknown input leads to a improper authentication vulnerability. CWE is classifying the issue as CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, an authentication bypass vulnerability allowed attackers with knowledge of a user's password to circumvent two-factor authentication (2FA) protections. When a user initiated login with valid credentials on a 2FA-enabled account, the system created a temporary session token before enforcing the second factor challenge. This token could be extracted and replayed via HTTP Basic Authentication to gain unauthorized access to authenticated endpoints. It is recommended that the Nextcloud Server is upgraded to 33.0.3 or 32.0.9. It is recommended that the Nextcloud Enterprise Server is upgraded to 33.0.3, 32.0.9, 31.0.14.5, 30.0.17.9 or 29.0.16.16

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-45690 since 05/13/2026. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available.

Upgrading to version 32.0.9 or 33.0.3 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Cloud Software

Vendor

• Nextcloud

Name

• Server

Version

• 32.0.0
• 32.0.1
• 32.0.2
• 32.0.3
• 32.0.4
• 32.0.5
• 32.0.6
• 32.0.7
• 32.0.8
• 33.0.0
• 33.0.1
• 33.0.2

License

• open-source

Website

• Product: https://github.com/nextcloud/server/

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