# CVE-2026-45543: Missing authorization in security-advisories

> Removed collaborators retain unauthorized read access to uploaded form response files due to lingering share permissions.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 1 Jun 2026
- **Updated:** 1 Jun 2026
- **Also known as:** GHSA-q4fw-6jf8-5vhh

## What is CVE-2026-45543?

CVE-2026-45543 is a medium-severity missing authorization vulnerability in nextcloud security-advisories, published on 1 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-552 (Files or Directories Accessible to External Parties)

## Which versions are affected by CVE-2026-45543?

It affects 1 product.


Products: Nextcloud Forms.

## How do I fix CVE-2026-45543?

No fix has been published for CVE-2026-45543 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-45543 being exploited?

There is no known exploitation of CVE-2026-45543 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-45543 and fix it if it is affected.

What it is: CVE-2026-45543 is a medium-severity missing authorization vulnerability in nextcloud security-advisories, published on 1 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-45543 in the wild and no public exploit code.

Affected product: nextcloud security-advisories. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-45543/ (Markdown: https://insights.sbomify.com/CVE-2026-45543/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-45543
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-45543
- OSV: https://osv.dev/vulnerability/CVE-2026-45543

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-45543/
Summaries are generated and may contain mistakes; the official description above is the record.