What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-01 · updated 2026-07-22
• Weakness: CWE-284

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

• nextcloud security-advisories: from 17.0.0, < 17.0.15; from 18.0.0, < 18.1.12; from 19.0.0, < 19.1.16; from 20.0.0, < 20.1.11; from 21.0.0, < 21.0.4

References

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

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