CVE-2026-45281 remediation guide
nextcloud security-advisories, nextcloud server
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, with the knowledge of other users’ principal URL an attacker could possibly send a request to gain full access to their calendar. Therefore, the attacker must be an authenticated user. This is because of improper authorization controls in the backend of the calendar. If the attacker had access to the calendar, they would be able to view and modify it. It is recommended that the Nextcloud Server is upgraded to 33.0.3 or 32.0.9. It is recommended...
Identify the affected asset
Confirm whether nextcloud security-advisories, nextcloud server is installed, record the deployed version and installation path, and identify exposed interfaces.
- Record the product name, package or appliance identifier, and installed version.
- Identify internet-facing, administrative, API, and internal access paths.
- Preserve the pre-change configuration and relevant service logs.
Validate the affected-version match
Compare the deployed version with the affected range: >= >= 32.0.0, < 32.0.9, >= >= 33.0.0, < 33.0.3, >= 32.0.0 < 32.0.9, >= 33.0.0 < 33.0.3, >= 21.0.0 < 21.0.9.23, >= 22.0.0 < 22.2.10.39, >= 23.0.0 < 23.0.12.35, >= 24.0.0 < 24.0.12.34, >= 25.0.0 < 25.0.13.29, >= 26.0.0 < 26.0.13.26, >= 27.0.0 < 27.1.11.26, >= 28.0.0 < 28.0.14.17, >= 29.0.0 < 29.0.16.16, >= 30.0.0 < 30.0.17.9, >= 31.0.0 < 31.0.14.5. Treat incomplete inventory results as unresolved.
Prioritize with independent signals
The CVSS severity warrants an early asset and exposure review. Combine this signal with asset criticality, exposure, compensating controls, and business impact.
Apply supported remediation
Follow the vendor advisory or supported update path. Current fixed-version status: 32.0.9, 33.0.3, 21.0.9.23, 22.2.10.39, 23.0.12.35, 24.0.12.34, 25.0.13.29, 26.0.13.26, 27.1.11.26, 28.0.14.17, 29.0.16.16, 30.0.17.9, 31.0.14.5. Preserve configuration and rollback material before change.
Verify the result
Confirm the resulting version, service health, authentication and access paths, monitoring coverage, and relevant security logs.
- Confirm the expected version and package state.
- Run a functional health check for critical service paths.
- Review authentication, error, application, and security monitoring logs.
- Reassess exposure if the supported fix cannot be applied.
Operational boundary
This page does not replace the vendor advisory, support contract, change-management process, or recovery plan. Do not infer that an asset is unaffected from an incomplete inventory query or a missing fixed-version field.