What’s Vulnerable › Vulnerabilities

CVE-2026-45543: Nextcloud: Deleting a Forms collaborator share leaves uploaded response files accessible through a lingering Files share

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% 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-552

Description

Nextcloud is an open source content collaboration platform. From version 4.3.0 to before version 5.2.7, a removed collaborator retains unauthorized read access to uploaded respondent files for the affected form. The scope is limited to uploaded files for forms where that user previously had results access. This issue has been patched in version 5.2.7.

Affected products

• nextcloud Forms: from 4.3.0 before 5.2.7 — fixed in 5.2.7

How to fix

Upgrade to a fixed version: nextcloud Forms 5.2.7. Check the vendor advisory for mitigations.

References

• https://github.com/nextcloud/forms/pull/3291
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-q4fw-6jf8-5vhh
• https://hackerone.com/reports/3617352

Get alerted when CVE-2026-45543 or the next vulnerability affects your stack