CVE-2026-45283Network attack vector

Cross-account file lock changes via unchecked DAV paths

Published Jun 1, 2026 · Updated Jun 1, 2026

Authorization bypass in Nextcloud Server 32.0.0 through 32.0.1 and 33.0.0 allows remote authenticated users to alter other users' file locks. The files_lock DAV backend resolves absolute WebDAV paths without verifying that the resulting file belongs to the authenticated account, and error responses expose token-owned lock tokens. Any authenticated account can therefore lock or unlock another user's files or use a disclosed token to remove a client lock; affected Enterprise Server releases include 31.0.0 through 31.0.14.3, 32.0.0 through 32.0.1, and 33.0.0.

CVSS severity6.3
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authorization bypass in Nextcloud Server 32.0.0 through 32.0.1 and 33.0.0 allows remote authenticated users to alter other users' file locks. The files_lock DAV backend resolves absolute WebDAV paths without verifying that the resulting file belongs to the authenticated account, and error responses expose token-owned lock tokens. Any authenticated account can therefore lock or unlock another user's files or use a disclosed token to remove a client lock; affected Enterprise Server releases include 31.0.0 through 31.0.14.3, 32.0.0 through 32.0.1, and 33.0.0.

The record

CVE
CVE-2026-45283
Published
Jun 1, 2026
Updated
Jun 1, 2026
Vendor
Nextcloud GmbH
Product
Nextcloud Security Advisories
Classifications
CWE-287
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, < 32.0.2
  2. Affected versionversion=>= 33.0.0, < 33.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Nextcloud Security Advisoriesversion=>= 32.0.0, < 32.0.2; version=>= 33.0.0, < 33.0.1

Published CVSS scores

6.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-287Improper Authentication

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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