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Medium severity · published Jun 1, 2026
CVE-2026-45264
Nextcloud: ACL Rename Permission Bypass in Team Folders Allows Unauthorized File Renames
4.3
CVSS
0.2%
EPSS
No
On KEV
Description
Nextcloud is an open source content collaboration platform. From versions 17.0.0 to before 17.0.15, 18.0.0 to before 18.1.12, 19.0.0 to before 19.1.16, 20.0.0 to before 20.1.11, and 21.0.0 to before 21.0.4, a user with READ and CREATE permission, but no UPDATE permission for a team folder can rename files in the team folder. This issue has been patched in versions 17.0.15, 18.1.12, 19.1.16, 20.1.11, and 21.0.4.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 14% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SE
security-advisories · nextcloud
>= 17.0.0, < 17.0.15; >= 18.0.0, < 18.1.12; >= 19.0.0, < 19.1.16; >= 20.0.0, < 20.1.11; >= 21.0.0, < 21.0.4 · source: vendor
Affected product
SE
security-advisories
nextcloud
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-45264
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-45264
github.com
https://github.com/nextcloud/groupfolders/pull/4361
github.com
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-wx2x-822r-rvmf
hackerone.com
https://hackerone.com/reports/3540673
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