CVE-2026-45543
Nextcloud: Deleting a Forms collaborator share leaves uploaded response files accessible through a lingering Files share
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.
INFO
Published Date :
June 1, 2026, 7:16 p.m.
Last Modified :
June 4, 2026, 4:43 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update Nextcloud to version 5.2.7 or later.
- Verify collaborator access controls.
- Review access logs for unauthorized activity.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-45543.
| URL | Resource |
|---|---|
| https://github.com/nextcloud/forms/pull/3291 | Issue Tracking Patch |
| https://github.com/nextcloud/security-advisories/security/advisories/GHSA-q4fw-6jf8-5vhh | Mitigation Vendor Advisory |
| https://hackerone.com/reports/3617352 | Permissions Required |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-45543 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-45543
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-45543 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-45543 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jun. 04, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:nextcloud:forms:*:*:*:*:*:*:*:* versions from (including) 4.3.0 up to (excluding) 5.2.7 Added Reference Type GitHub, Inc.: https://github.com/nextcloud/forms/pull/3291 Types: Issue Tracking, Patch Added Reference Type GitHub, Inc.: https://github.com/nextcloud/security-advisories/security/advisories/GHSA-q4fw-6jf8-5vhh Types: Mitigation, Vendor Advisory Added Reference Type GitHub, Inc.: https://hackerone.com/reports/3617352 Types: Permissions Required -
New CVE Received by [email protected]
Jun. 01, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Added CWE CWE-552 Added Reference https://github.com/nextcloud/forms/pull/3291 Added Reference https://github.com/nextcloud/security-advisories/security/advisories/GHSA-q4fw-6jf8-5vhh Added Reference https://hackerone.com/reports/3617352