CVE-2026-45283

Description

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.2, and 33.0.0 to before 33.0.1, the files_lock app did not properly validate the ownership of files when processing DAV lock and unlock requests. An authenticated user could lock or unlock files belonging to other users by targeting their absolute WebDAV paths. Additionally, lock tokens were disclosed to unauthorized callers in error responses, allowing attackers to remove token-based locks placed by other users' client applications. It is recommended that the Nextcloud Server is upgraded to 32.0.2 or 33.0.1. It is recommended that the Nextcloud Enterprise Server is upgraded to 31.0.14.4 or 32.0.2 or 33.0.1

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CVSS v3.1 Score

6.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

EPSS — Exploit Prediction

0.0021

Probability of exploitation

0.11%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-287 Improper Authentication

Affected Products

Vendor	Product	Versions
nextcloud	nextcloud_server	32.0.0 — 32.0.2
nextcloud	nextcloud_server	33.0.0 — 33.0.1
nextcloud	nextcloud_server	31.0.0 — 31.0.14.4
nextcloud	nextcloud_server	32.0.0 — 32.0.2
nextcloud	nextcloud_server	33.0.0 — 33.0.1

References

Advisories & Patches

https://github.com/nextcloud/files_lock/pull/1007 https://github.com/nextcloud/security-advisories/security/advisories/GHSA-4chh-6mhf-p4jj

Other References

https://hackerone.com/reports/3301553#

Frequently Asked Questions

What is CVE-2026-45283? +

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.2, and 33.0.0 to before 33.0.1, the files_lock app did not properly validate the ownership of files when processing DAV lock and unlock requests. An authenticated user could lock or unlock files belonging to other users by targeting their absolute WebDAV paths. Additionally, lock tokens were disclosed to unauthorized callers in error responses, allowing attackers to remove token-based locks placed by other users' client applications. It is recommended that the Nextcloud Server is upgraded to 32.0.2 or 33.0.1. It is recommended that the Nextcloud Enterprise Server is upgraded to 31.0.14.4 or 32.0.2 or 33.0.1 It has a CVSS v3.1 base score of 6.3 (MEDIUM).

How severe is CVE-2026-45283? +

CVE-2026-45283 has a CVSS v3.1 score of 6.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0021, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-45283? +

CVE-2026-45283 affects products from nextcloud, specifically: nextcloud_server. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-45283? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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