Vulnerability · Published Jun 1, 2026 · Assigned by GitHub_M

CVE-2026-45264Nextcloud: ACL Rename Permission Bypass in Team Folders Allows Unauthorized File Renames

Medium 4.3

In plain English

A medium-severity improper access control in security-advisories from nextcloud. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 14% of all known vulnerabilities).

Severity (CVSS 3.1)4.3Medium

Exploit odds (30 days)0.2%top 86.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
nextcloud	security-advisories	>= 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

Weakness: CWE-284 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-wx2x-822r-rvmf x_refsource_CONFIRM
https://github.com/nextcloud/groupfolders/pull/4361 x_refsource_MISC
https://hackerone.com/reports/3540673 x_refsource_MISC