Nextcloud Team Folders up to 21.0.3 access control

Summaryinfo

A vulnerability classified as critical has been found in Nextcloud Team Folders up to 17.0.14/18.1.11/19.1.15/20.1.10/21.0.3. This impacts an unknown function. Performing a manipulation results in access control. This vulnerability is known as CVE-2026-45264. Remote exploitation of the attack is possible. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Nextcloud Team Folders up to 17.0.14/18.1.11/19.1.15/20.1.10/21.0.3. This affects some unknown processing. The manipulation with an unknown input leads to a access control vulnerability. CWE is classifying the issue as CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. 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. From versions 17.0.0 to before 17.0.15, 18.0.0 to before 18.1.12, 19.0.0 to before 19.1.16, 20.0.0 to before 20.1.11, and 21.0.0 to before 21.0.4, a user with READ and CREATE permission, but no UPDATE permission for a team folder can rename files in the team folder. This issue has been patched in versions 17.0.15, 18.1.12, 19.1.16, 20.1.11, and 21.0.4.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-45264 since 05/11/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

Upgrading to version 17.0.15, 18.1.12, 19.1.16, 20.1.11 or 21.0.4 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

• Team Folders

Version

• 17.0.0
• 17.0.1
• 17.0.2
• 17.0.3
• 17.0.4
• 17.0.5
• 17.0.6
• 17.0.7
• 17.0.8
• 17.0.9
• 17.0.10
• 17.0.11
• 17.0.12
• 17.0.13
• 17.0.14
• 18.1.0
• 18.1.1
• 18.1.2
• 18.1.3
• 18.1.4
• 18.1.5
• 18.1.6
• 18.1.7
• 18.1.8
• 18.1.9
• 18.1.10
• 18.1.11
• 19.1.0
• 19.1.1
• 19.1.2
• 19.1.3
• 19.1.4
• 19.1.5
• 19.1.6
• 19.1.7
• 19.1.8
• 19.1.9
• 19.1.10
• 19.1.11
• 19.1.12
• 19.1.13
• 19.1.14
• 19.1.15
• 20.1.0
• 20.1.1
• 20.1.2
• 20.1.3
• 20.1.4
• 20.1.5
• 20.1.6
• 20.1.7
• 20.1.8
• 20.1.9
• 20.1.10
• 21.0.0
• 21.0.1
• 21.0.2
• 21.0.3

License

• open-source

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