Nextcloud End-to-End Encryption up to 1.15.3/1.16.2/1.17.0/1.18.0 authorization

Summaryinfo

A vulnerability described as problematic has been identified in Nextcloud End-to-End Encryption up to 1.15.3/1.16.2/1.17.0/1.18.0. This affects an unknown function. Such manipulation leads to authorization. This vulnerability is traded as CVE-2026-45159. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Nextcloud End-to-End Encryption up to 1.15.3/1.16.2/1.17.0/1.18.0. It has been rated as problematic. Affected by this issue is an unknown code block. The manipulation with an unknown input leads to a authorization vulnerability. Using CWE to declare the problem leads to CWE-639. The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. Impacted is integrity. CVE summarizes:

Nextcloud is an open source content collaboration platform. From versions 1.15.0 to before 1.15.4, 1.16.0 to before 1.16.3, 1.17.0 to before 1.17.1, and 1.18.0 to before 1.18.1, a malicious user with access to an end-to-end encrypted files drop link was able to also drop files into other end-to-end encrypted folders of the share owner. Reading and modifying of other files was not possible. This issue has been patched in versions 1.15.4, 1.16.3, 1.17.1, 1.18.1, and 2.0.0-rc.7.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-45159 since 05/08/2026. The exploitation is known to be easy. The attack may be launched remotely. Successful exploitation requires user interaction by the victim. The technical details are unknown and an exploit is not available.

Upgrading to version 1.15.4, 1.16.3, 1.17.1 or 1.18.1 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

• End-to-End Encryption

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.15.0
• 1.15.1
• 1.15.2
• 1.15.3
• 1.16
• 1.16.0
• 1.16.1
• 1.16.2
• 1.17
• 1.17.0
• 1.18.0

License

• open-source

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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