Description
Nextcloud Server 30.0.0 is vulnerable to an Insecure Direct Object Reference (IDOR) in the /core/preview endpoint. Any authenticated user can access previews of arbitrary files belonging to other users by manipulating the fileId parameter. This allows unauthorized disclosure of sensitive data, such as text files or images, without prior sharing permissions.
References (3)
Core 3
Core References
Exploit, Third Party Advisory
https://gist.github.com/tarekramm/586dfe2d113fedfee6d71182570fc090
Product
https://nextcloud.com
Scores
CVSS v3
4.3
EPSS
0.0004
EPSS Percentile
10.9%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
CWE
CWE-639
Status
published
Products (1)
nextcloud/nextcloud_server
30.0.0
Published
Dec 12, 2025
Tracked Since
Feb 18, 2026