CVE-2026-45157: CWE-284: Improper Access Control in nextcloud security-advisories
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
AI Analysis
Technical Summary
CVE-2026-45157 is an improper access control vulnerability (CWE-284) in Nextcloud Server affecting versions 32.0.0 to before 32.0.9 and 33.0.0 to before 33.0.3. The flaw allows a user with access to a file share to leverage the share token to access chunked upload endpoints directly, exposing temporary part files during uploads. This exposure could result in unauthorized access to partial file data. The vulnerability is addressed by upgrading to Nextcloud Server 32.0.9 or 33.0.3, or the corresponding patched Enterprise Server versions.
Potential Impact
The vulnerability allows unauthorized disclosure of temporary upload parts to users who have access to a file share, potentially exposing partial file contents during upload. The CVSS score of 6.3 reflects a medium severity with high confidentiality impact, low integrity impact, and no availability impact. There are no known exploits in the wild at this time.
Mitigation Recommendations
A fix is available by upgrading Nextcloud Server to version 32.0.9 or 33.0.3. For Nextcloud Enterprise Server, upgrade to one of the patched versions: 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. No additional mitigation steps are indicated by the vendor advisory.
CVE-2026-45157: CWE-284: Improper Access Control in nextcloud security-advisories
Description
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
CVSS v3.1
Score 6.3medium
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-45157 is an improper access control vulnerability (CWE-284) in Nextcloud Server affecting versions 32.0.0 to before 32.0.9 and 33.0.0 to before 33.0.3. The flaw allows a user with access to a file share to leverage the share token to access chunked upload endpoints directly, exposing temporary part files during uploads. This exposure could result in unauthorized access to partial file data. The vulnerability is addressed by upgrading to Nextcloud Server 32.0.9 or 33.0.3, or the corresponding patched Enterprise Server versions.
Potential Impact
The vulnerability allows unauthorized disclosure of temporary upload parts to users who have access to a file share, potentially exposing partial file contents during upload. The CVSS score of 6.3 reflects a medium severity with high confidentiality impact, low integrity impact, and no availability impact. There are no known exploits in the wild at this time.
Mitigation Recommendations
A fix is available by upgrading Nextcloud Server to version 32.0.9 or 33.0.3. For Nextcloud Enterprise Server, upgrade to one of the patched versions: 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. No additional mitigation steps are indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-05-08T20:44:38.964Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a1dbba3e29bf47b501c57bf
Added to database: 6/1/2026, 5:04:35 PM
Last enriched: 6/1/2026, 5:20:30 PM
Last updated: 6/2/2026, 4:03:49 AM
Views: 9
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