CVE intelligence and bounded remediation
CVE-2026-45157 — Nextcloud is an open source content collaboration platform
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, when a malicious user has access to a file share of a user, they could use this share token to also access the chunking upload directly and see temporary part files during on going uploads. It is recommended that the Nextcloud Server is upgraded to 32.0.9 or 33.0.3. It is recommended that the Nextcloud Enterprise Server is upgraded to 26.0.13.26, 27.1.11.25, 28.0.14.17, 29.0.16.16, 30.0.17.9, 31.0.14.5, 32.0.9 or 33.0.3
- Severity
- Medium
- CVSS
- 6.3 (3.1)
- Published
- 2026-06-01
- CISA KEV
- Not currently listed
- Ecosystem
- software/application
- Weaknesses
- CWE-284
Affected products
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Matched remediation archetype
Authorization bypass, IDOR, and cross-tenant access
This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.
Check exposure
- Map object and action authorization checks across API, UI, batch, import/export, and background-job paths.
- Identify tenant, ownership, role, and policy boundaries for affected resources and administrative operations.
- Use synthetic fixtures to compare intended access matrices without accessing another user's real data.
Remediate safely
- Enforce server-side authorization at each resource access and state transition using the authenticated principal and trusted tenant context.
- Scope data queries by tenant and ownership; treat client-supplied identifiers, roles, and policy claims as untrusted.
- Add deny-by-default policy tests for horizontal and vertical access across every affected transport.
Authoritative sources
Complete CVE record and remediation plan
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