CVE-2026-45157Network attack vector

Upload-part disclosure via enumerable DAV intermediates

Published Jun 1, 2026 · Updated Jun 1, 2026

Improper access control in Nextcloud Server allows remote authenticated users with a valid share token to read temporary upload-part files. The DAV ChunkingV2Plugin resolves GET requests for FutureFile and UploadFile nodes, while the upload collection returns its child entries rather than blocking enumeration. The share owner must have an upload in progress, and the reported consequence is disclosure of temporary part-file contents.

CVSS severity6.3
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Nextcloud Server allows remote authenticated users with a valid share token to read temporary upload-part files. The DAV ChunkingV2Plugin resolves GET requests for FutureFile and UploadFile nodes, while the upload collection returns its child entries rather than blocking enumeration. The share owner must have an upload in progress, and the reported consequence is disclosure of temporary part-file contents.

The record

CVE
CVE-2026-45157
Published
Jun 1, 2026
Updated
Jun 1, 2026
Vendor
Nextcloud GmbH
Product
Security Advisories
Classifications
CWE-284, T1005, T1083
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 32.0.0, < 32.0.9
  2. Affected versionversion=>= 33.0.0, < 33.0.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Security Advisoriesversion=>= 32.0.0, < 32.0.9; version=>= 33.0.0, < 33.0.3

Published CVSS scores

6.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control
T1005Data from Local System
T1083File and Directory Discovery

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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